summaryrefslogtreecommitdiff
path: root/libstdc++-v3/acinclude.m4
blob: b9f5d3fc1af26ed5a81cf61b2c82bf243f8ea87c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378

dnl
dnl GLIBCXX_CONDITIONAL (NAME, SHELL-TEST)
dnl
dnl Exactly like AM_CONDITIONAL, but delays evaluation of the test until the
dnl end of configure.  This lets tested variables be reassigned, and the
dnl conditional will depend on the final state of the variable.  For a simple
dnl example of why this is needed, see GLIBCXX_ENABLE_HOSTED.
dnl
m4_define([_m4_divert(glibcxx_diversion)], 8000)dnl
AC_DEFUN([GLIBCXX_CONDITIONAL], [dnl
  m4_divert_text([glibcxx_diversion],dnl
   AM_CONDITIONAL([$1],[$2])
  )dnl
])dnl
AC_DEFUN([GLIBCXX_EVALUATE_CONDITIONALS], [m4_undivert([glibcxx_diversion])])dnl


dnl
dnl Check to see what architecture and operating system we are compiling
dnl for.  Also, if architecture- or OS-specific flags are required for
dnl compilation, pick them up here.
dnl
AC_DEFUN([GLIBCXX_CHECK_HOST], [
  . $glibcxx_srcdir/configure.host
  AC_MSG_NOTICE([CPU config directory is $cpu_include_dir])
  AC_MSG_NOTICE([OS config directory is $os_include_dir])
])

dnl
dnl Initialize the rest of the library configury.  At this point we have
dnl variables like $host.
dnl
dnl Sets:
dnl  SUBDIRS
dnl Substs:
dnl  glibcxx_builddir     (absolute path)
dnl  glibcxx_srcdir       (absolute path)
dnl  toplevel_srcdir      (absolute path)
dnl  with_cross_host
dnl  with_newlib
dnl  with_target_subdir
dnl plus
dnl  - the variables in GLIBCXX_CHECK_HOST / configure.host
dnl  - default settings for all AM_CONFITIONAL test variables
dnl  - lots of tools, like CC and CXX
dnl
AC_DEFUN([GLIBCXX_CONFIGURE], [
  # Keep these sync'd with the list in Makefile.am.  The first provides an
  # expandable list at autoconf time; the second provides an expandable list
  # (i.e., shell variable) at configure time.
  m4_define([glibcxx_SUBDIRS],[include libmath libsupc++ src po testsuite])
  SUBDIRS='glibcxx_SUBDIRS'

  # These need to be absolute paths, yet at the same time need to
  # canonicalize only relative paths, because then amd will not unmount
  # drives. Thus the use of PWDCMD: set it to 'pawd' or 'amq -w' if using amd.
  glibcxx_builddir=`${PWDCMD-pwd}`
  case $srcdir in
    [\\/$]* | ?:[\\/]*) glibcxx_srcdir=${srcdir} ;;
    *) glibcxx_srcdir=`cd "$srcdir" && ${PWDCMD-pwd} || echo "$srcdir"` ;;
  esac
  toplevel_srcdir=${glibcxx_srcdir}/..
  AC_SUBST(glibcxx_builddir)
  AC_SUBST(glibcxx_srcdir)
  AC_SUBST(toplevel_srcdir)

  # We use these options to decide which functions to include.  They are
  # set from the top level.
  AC_ARG_WITH([target-subdir],
    AC_HELP_STRING([--with-target-subdir=SUBDIR],
                   [configuring in a subdirectory]))

  AC_ARG_WITH([cross-host],
    AC_HELP_STRING([--with-cross-host=HOST],
                   [configuring with a cross compiler]))

  AC_ARG_WITH([newlib],
    AC_HELP_STRING([--with-newlib],
                   [assume newlib as a system C library]))

  # We're almost certainly being configured before anything else which uses
  # C++, so all of our AC_PROG_* discoveries will be cached.  It's vital that
  # we not cache the value of CXX that we "discover" here, because it's set
  # to something unique for us and libjava.  Other target libraries need to
  # find CXX for themselves.  We yank the rug out from under the normal AC_*
  # process by sneakily renaming the cache variable.  This also lets us debug
  # the value of "our" CXX in postmortems.
  #
  # We must also force CXX to /not/ be a precious variable, otherwise the
  # wrong (non-multilib-adjusted) value will be used in multilibs.  This
  # little trick also affects CPPFLAGS, CXXFLAGS, and LDFLAGS.  And as a side
  # effect, CXXFLAGS is no longer automagically subst'd, so we have to do
  # that ourselves.  Un-preciousing AC_PROG_CC also affects CC and CFLAGS.
  #
  # -fno-builtin must be present here so that a non-conflicting form of
  # std::exit can be guessed by AC_PROG_CXX, and used in later tests.

  m4_define([ac_cv_prog_CXX],[glibcxx_cv_prog_CXX])
  m4_rename([_AC_ARG_VAR_PRECIOUS],[glibcxx_PRECIOUS])
  m4_define([_AC_ARG_VAR_PRECIOUS],[])
  save_CXXFLAGS="$CXXFLAGS"
  CXXFLAGS="$CXXFLAGS -fno-builtin"
  AC_PROG_CC
  AC_PROG_CXX
  CXXFLAGS="$save_CXXFLAGS"
  m4_rename([glibcxx_PRECIOUS],[_AC_ARG_VAR_PRECIOUS])
  AC_SUBST(CFLAGS)
  AC_SUBST(CXXFLAGS)

  # Will set LN_S to either 'ln -s', 'ln', or 'cp -p' (if linking isn't
  # available).  Uncomment the next line to force a particular method.
  AC_PROG_LN_S
  #LN_S='cp -p'

  AC_CHECK_TOOL(AS, as)
  AC_CHECK_TOOL(AR, ar)
  AC_CHECK_TOOL(RANLIB, ranlib, ranlib-not-found-in-path-error)

  AM_MAINTAINER_MODE

  # Set up safe default values for all subsequent AM_CONDITIONAL tests
  # which are themselves conditionally expanded.
  ## (Right now, this only matters for enable_wchar_t, but nothing prevents
  ## other macros from doing the same.  This should be automated.)  -pme
  need_libmath=no

  # Check for uClibc since Linux platforms use different configuration
  # directories depending on the C library in use.
  AC_EGREP_CPP([_using_uclibc], [
  #include <stdio.h>
  #if __UCLIBC__
    _using_uclibc
  #endif
  ], uclibc=yes, uclibc=no)

  # Find platform-specific directories containing configuration info.
  # Also possibly modify flags used elsewhere, as needed by the platform.
  GLIBCXX_CHECK_HOST
])


dnl
dnl Tests for newer compiler features, or features that are present in newer
dnl compiler versions but not older compiler versions still in use, should
dnl be placed here.
dnl
dnl Defines:
dnl  WERROR='-Werror' if requested and possible; g++'s that lack the
dnl   new inlining code or the new system_header pragma will die on -Werror.
dnl   Leave it out by default and use maint-mode to use it.
dnl  SECTION_FLAGS='-ffunction-sections -fdata-sections' if
dnl   compiler supports it and the user has not requested debug mode.
dnl
AC_DEFUN([GLIBCXX_CHECK_COMPILER_FEATURES], [
  # All these tests are for C++; save the language and the compiler flags.
  # The CXXFLAGS thing is suspicious, but based on similar bits previously
  # found in GLIBCXX_CONFIGURE.
  AC_LANG_SAVE
  AC_LANG_CPLUSPLUS
  ac_test_CXXFLAGS="${CXXFLAGS+set}"
  ac_save_CXXFLAGS="$CXXFLAGS"

  # Check for maintainer-mode bits.
  if test x"$USE_MAINTAINER_MODE" = xno; then
    WERROR=''
  else
    WERROR='-Werror'
  fi

  # Check for -ffunction-sections -fdata-sections
  AC_MSG_CHECKING([for g++ that supports -ffunction-sections -fdata-sections])
  CXXFLAGS='-Werror -ffunction-sections -fdata-sections'
  AC_TRY_COMPILE(, [int foo;], [ac_fdsections=yes], [ac_fdsections=no])
  if test "$ac_test_CXXFLAGS" = set; then
    CXXFLAGS="$ac_save_CXXFLAGS"
  else
    # this is the suspicious part
    CXXFLAGS=''
  fi
  if test x"$ac_fdsections" = x"yes"; then
    SECTION_FLAGS='-ffunction-sections -fdata-sections'
  fi
  AC_MSG_RESULT($ac_fdsections)

  AC_LANG_RESTORE
  AC_SUBST(WERROR)
  AC_SUBST(SECTION_FLAGS)
])


dnl
dnl If GNU ld is in use, check to see if tricky linker opts can be used.  If
dnl the native linker is in use, all variables will be defined to something
dnl safe (like an empty string).
dnl
dnl Defines:
dnl  SECTION_LDFLAGS='-Wl,--gc-sections' if possible
dnl  OPT_LDFLAGS='-Wl,-O1' and '-z,relro' if possible
dnl  LD (as a side effect of testing)
dnl Sets:
dnl  with_gnu_ld
dnl  glibcxx_gnu_ld_version (possibly)
dnl
dnl The last will be a single integer, e.g., version 1.23.45.0.67.89 will
dnl set glibcxx_gnu_ld_version to 12345.  Zeros cause problems.
dnl
AC_DEFUN([GLIBCXX_CHECK_LINKER_FEATURES], [
  # If we're not using GNU ld, then there's no point in even trying these
  # tests.  Check for that first.  We should have already tested for gld
  # by now (in libtool), but require it now just to be safe...
  test -z "$SECTION_LDFLAGS" && SECTION_LDFLAGS=''
  test -z "$OPT_LDFLAGS" && OPT_LDFLAGS=''
  AC_REQUIRE([AC_PROG_LD])
  AC_REQUIRE([AC_PROG_AWK])

  # The name set by libtool depends on the version of libtool.  Shame on us
  # for depending on an impl detail, but c'est la vie.  Older versions used
  # ac_cv_prog_gnu_ld, but now it's lt_cv_prog_gnu_ld, and is copied back on
  # top of with_gnu_ld (which is also set by --with-gnu-ld, so that actually
  # makes sense).  We'll test with_gnu_ld everywhere else, so if that isn't
  # set (hence we're using an older libtool), then set it.
  if test x${with_gnu_ld+set} != xset; then
    if test x${ac_cv_prog_gnu_ld+set} != xset; then
      # We got through "ac_require(ac_prog_ld)" and still not set?  Huh?
      with_gnu_ld=no
    else
      with_gnu_ld=$ac_cv_prog_gnu_ld
    fi
  fi

  # Start by getting the version number.  I think the libtool test already
  # does some of this, but throws away the result.
  if test x"$with_gnu_ld" = x"yes"; then
    AC_MSG_CHECKING([for ld version])
    changequote(,)
    ldver=`$LD --version 2>/dev/null | head -1 | \
           sed -e 's/GNU ld version \([0-9.][0-9.]*\).*/\1/'`
    changequote([,])
    glibcxx_gnu_ld_version=`echo $ldver | \
           $AWK -F. '{ if (NF<3) [$]3=0; print ([$]1*100+[$]2)*100+[$]3 }'`
    AC_MSG_RESULT($glibcxx_gnu_ld_version)
  fi

  # Set --gc-sections.
  glibcxx_gcsections_min_ld=21602
  if test x"$with_gnu_ld" = x"yes" && 
	test $glibcxx_gnu_ld_version -gt $glibcxx_gcsections_min_ld ; then

    # Sufficiently young GNU ld it is!  Joy and bunny rabbits!
    # NB: This flag only works reliably after 2.16.1. Configure tests
    # for this are difficult, so hard wire a value that should work.

    # All these tests are for C++, but run with the "C" compiler driver.
    # Need to do this so that g++ won't try to link in libstdc++/libsupc++.
    ac_test_CFLAGS="${CFLAGS+set}"
    ac_save_CFLAGS="$CFLAGS"
    CFLAGS='-x c++ -Wl,--gc-sections'

    # Check for -Wl,--gc-sections
    AC_MSG_CHECKING([for ld that supports -Wl,--gc-sections])
    AC_TRY_LINK([ int one(void) { return 1; }
     int two(void) { return 2; }
	], [ two(); ] , [ac_gcsections=yes], [ac_gcsections=no])
    if test "$ac_gcsections" = "yes"; then
      rm -f conftest.c
      touch conftest.c
      if $CC -c conftest.c; then
	if $LD --gc-sections -o conftest conftest.o 2>&1 | \
	   grep "Warning: gc-sections option ignored" > /dev/null; then
	  ac_gcsections=no
	fi
      fi
      rm -f conftest.c conftest.o conftest
    fi
    if test "$ac_gcsections" = "yes"; then
      SECTION_LDFLAGS="-Wl,--gc-sections $SECTION_LDFLAGS"
    fi
    AC_MSG_RESULT($ac_gcsections)

    if test "$ac_test_CFLAGS" = set; then
      CFLAGS="$ac_save_CFLAGS"
    else
      # this is the suspicious part
      CFLAGS=''
    fi
  fi

  # Set -z,relro.
  # Note this is only for shared objects.
  ac_ld_relro=no
  if test x"$with_gnu_ld" = x"yes"; then
    AC_MSG_CHECKING([for ld that supports -Wl,-z,relro])
    cxx_z_relo=`$LD -v --help 2>/dev/null | grep "z relro"`
    if test -n "$cxx_z_relo"; then
      OPT_LDFLAGS="-Wl,-z,relro"
      ac_ld_relro=yes
    fi
    AC_MSG_RESULT($ac_ld_relro)
  fi

  # Set linker optimization flags.
  if test x"$with_gnu_ld" = x"yes"; then
    OPT_LDFLAGS="-Wl,-O1 $OPT_LDFLAGS"
  fi

  AC_SUBST(SECTION_LDFLAGS)
  AC_SUBST(OPT_LDFLAGS)
])


dnl
dnl Check to see if this target can enable the iconv specializations.
dnl If --disable-c-mbchar was given, no wchar_t specialization is enabled.  
dnl (This must have been previously checked, along with the rest of C99 
dnl support.) By default, iconv support is disabled.
dnl
dnl Defines:
dnl  _GLIBCXX_USE_ICONV if all the bits are found.
dnl Substs:
dnl  LIBICONV to a -l string containing the iconv library, if needed.
dnl
AC_DEFUN([GLIBCXX_CHECK_ICONV_SUPPORT], [

  enable_iconv=no
  # Only continue checking if the ISO C99 headers exist and support is on.
  if test x"$enable_wchar_t" = xyes; then

    # From Bruno Haible's AM_ICONV, but without link tests.
    # Check for existence of libiconv.a providing XPG2 wchar_t support.
    # Some systems have iconv in libc, some have it in libiconv (OSF/1 and
    # those with the standalone portable GNU libiconv installed).
    AC_ARG_WITH([libiconv-prefix],
[  --with-libiconv-prefix=DIR  search for libiconv in DIR/include and DIR/lib], [  for dir in `echo "$withval" | tr : ' '`; do
      if test -d $dir/include; then CPPFLAGS="$CPPFLAGS -I$dir/include"; fi
      if test -d $dir/lib; then LIBICONV="$LIBICONV -L$dir/lib"; fi
    done
    LIBICONV="$LIBICONV -liconv"
   ])
   if test x"$LIBICONV" != x; then
     AC_MSG_NOTICE([--with-libiconv-prefix is $LIBICONV])
   fi

    # Use iconv for wchar_t to char conversions. As such, check for
    # X/Open Portability Guide, version 2 features (XPG2).
    AC_CHECK_HEADER(iconv.h, ac_has_iconv_h=yes, ac_has_iconv_h=no)
    AC_CHECK_HEADER(langinfo.h, ac_has_langinfo_h=yes, ac_has_langinfo_h=no)

    ac_save_LIBS="$LIBS"
    LIBS="$LIBS $LIBICONV"
    AC_CHECK_FUNCS([iconv_open iconv_close iconv nl_langinfo],
    [ac_XPG2funcs=yes], [ac_XPG2funcs=no])
    LIBS="$ac_save_LIBS"

    if test x"$ac_has_iconv_h" = xyes &&
       test x"$ac_has_langinfo_h" = xyes &&
       test x"$ac_XPG2funcs" = xyes;
    then
      AC_DEFINE([_GLIBCXX_USE_ICONV],1,
	        [Define if iconv and related functions exist and are usable.])
      enable_iconv=yes
      AC_SUBST(LIBICONV)
    fi
  fi
  AC_MSG_CHECKING([for enabled iconv specializations])
  AC_MSG_RESULT($enable_iconv)
])


dnl
dnl Check for headers for, and arguments to, the setrlimit() function.
dnl Used only in testsuite_hooks.h.  Called from GLIBCXX_CONFIGURE_TESTSUITE.
dnl
dnl Defines:
dnl  _GLIBCXX_RES_LIMITS if we can set artificial resource limits 
dnl  various HAVE_LIMIT_* for individual limit names
dnl
AC_DEFUN([GLIBCXX_CHECK_SETRLIMIT_ancilliary], [
  AC_MSG_CHECKING([for RLIMIT_$1])
  AC_TRY_COMPILE(
    [#include <unistd.h>
     #include <sys/time.h>
     #include <sys/resource.h>
    ],
    [ int f = RLIMIT_$1 ; ],
    [glibcxx_mresult=1], [glibcxx_mresult=0])
  AC_DEFINE_UNQUOTED(HAVE_LIMIT_$1, $glibcxx_mresult,
                     [Only used in build directory testsuite_hooks.h.])
  if test $glibcxx_mresult = 1 ; then res=yes ; else res=no ; fi
  AC_MSG_RESULT($res)
])

AC_DEFUN([GLIBCXX_CHECK_SETRLIMIT], [
  setrlimit_have_headers=yes
  AC_CHECK_HEADERS(unistd.h sys/time.h sys/resource.h,
                   [],
                   [setrlimit_have_headers=no])
  # If don't have the headers, then we can't run the tests now, and we
  # won't be seeing any of these during testsuite compilation.
  if test $setrlimit_have_headers = yes; then
    # Can't do these in a loop, else the resulting syntax is wrong.
    GLIBCXX_CHECK_SETRLIMIT_ancilliary(DATA)
    GLIBCXX_CHECK_SETRLIMIT_ancilliary(RSS)
    GLIBCXX_CHECK_SETRLIMIT_ancilliary(VMEM)
    GLIBCXX_CHECK_SETRLIMIT_ancilliary(AS)
    GLIBCXX_CHECK_SETRLIMIT_ancilliary(FSIZE)

    # Check for rlimit, setrlimit.
    AC_CACHE_VAL(ac_setrlimit, [
      AC_TRY_COMPILE(
        [#include <unistd.h>
         #include <sys/time.h>
         #include <sys/resource.h>
        ],
        [struct rlimit r;
         setrlimit(0, &r);],
        [ac_setrlimit=yes], [ac_setrlimit=no])
    ])
  fi

  AC_MSG_CHECKING([for testsuite resource limits support])
  if test $setrlimit_have_headers = yes && test $ac_setrlimit = yes; then
    ac_res_limits=yes
    AC_DEFINE(_GLIBCXX_RES_LIMITS, 1,
              [Define if using setrlimit to set resource limits during
              "make check"])
  else
    ac_res_limits=no
  fi
  AC_MSG_RESULT($ac_res_limits)
])


dnl
dnl Check whether S_ISREG (Posix) or S_IFREG is available in <sys/stat.h>.
dnl Define HAVE_S_ISREG / HAVE_S_IFREG appropriately.
dnl
AC_DEFUN([GLIBCXX_CHECK_S_ISREG_OR_S_IFREG], [
  AC_MSG_CHECKING([for S_ISREG or S_IFREG])
  AC_CACHE_VAL(glibcxx_cv_S_ISREG, [
    AC_TRY_LINK(
      [#include <sys/stat.h>],
      [struct stat buffer;
       fstat(0, &buffer);
       S_ISREG(buffer.st_mode);],
      [glibcxx_cv_S_ISREG=yes],
      [glibcxx_cv_S_ISREG=no])
  ])
  AC_CACHE_VAL(glibcxx_cv_S_IFREG, [
    AC_TRY_LINK(
      [#include <sys/stat.h>],
      [struct stat buffer;
       fstat(0, &buffer);
       S_IFREG & buffer.st_mode;],
      [glibcxx_cv_S_IFREG=yes],
      [glibcxx_cv_S_IFREG=no])
  ])
  res=no
  if test $glibcxx_cv_S_ISREG = yes; then
    AC_DEFINE(HAVE_S_ISREG, 1, 
              [Define if S_IFREG is available in <sys/stat.h>.])
    res=S_ISREG
  elif test $glibcxx_cv_S_IFREG = yes; then
    AC_DEFINE(HAVE_S_IFREG, 1,
              [Define if S_IFREG is available in <sys/stat.h>.])
    res=S_IFREG
  fi
  AC_MSG_RESULT($res)
])


dnl
dnl Check whether poll is available in <poll.h>, and define HAVE_POLL.
dnl
AC_DEFUN([GLIBCXX_CHECK_POLL], [
  AC_MSG_CHECKING([for poll])
  AC_CACHE_VAL(glibcxx_cv_POLL, [
    AC_TRY_LINK(
      [#include <poll.h>],
      [struct pollfd pfd[1];
       pfd[0].events = POLLIN;
       poll(pfd, 1, 0);],
      [glibcxx_cv_POLL=yes],
      [glibcxx_cv_POLL=no])
  ])
  if test $glibcxx_cv_POLL = yes; then
    AC_DEFINE(HAVE_POLL, 1, [Define if poll is available in <poll.h>.])
  fi
  AC_MSG_RESULT($glibcxx_cv_POLL)
])


dnl
dnl Check whether writev is available in <sys/uio.h>, and define HAVE_WRITEV.
dnl
AC_DEFUN([GLIBCXX_CHECK_WRITEV], [
  AC_MSG_CHECKING([for writev])
  AC_CACHE_VAL(glibcxx_cv_WRITEV, [
    AC_TRY_LINK(
      [#include <sys/uio.h>],
      [struct iovec iov[2];
       writev(0, iov, 0);],
      [glibcxx_cv_WRITEV=yes],
      [glibcxx_cv_WRITEV=no])
  ])
  if test $glibcxx_cv_WRITEV = yes; then
    AC_DEFINE(HAVE_WRITEV, 1, [Define if writev is available in <sys/uio.h>.])
  fi
  AC_MSG_RESULT($glibcxx_cv_WRITEV)
])


dnl
dnl Check whether int64_t is available in <stdint.h>, and define HAVE_INT64_T.
dnl
AC_DEFUN([GLIBCXX_CHECK_INT64_T], [
  AC_MSG_CHECKING([for int64_t])
  AC_CACHE_VAL(glibcxx_cv_INT64_T, [
    AC_TRY_COMPILE(
      [#include <stdint.h>],
      [int64_t var;],
      [glibcxx_cv_INT64_T=yes],
      [glibcxx_cv_INT64_T=no])
  ])
  if test $glibcxx_cv_INT64_T = yes; then
    AC_DEFINE(HAVE_INT64_T, 1, [Define if int64_t is available in <stdint.h>.])
  fi
  AC_MSG_RESULT($glibcxx_cv_INT64_T)
])


dnl
dnl Check whether LFS support is available.
dnl
AC_DEFUN([GLIBCXX_CHECK_LFS], [
  AC_LANG_SAVE
  AC_LANG_CPLUSPLUS
  ac_save_CXXFLAGS="$CXXFLAGS"
  CXXFLAGS="$CXXFLAGS -fno-exceptions"	
  AC_MSG_CHECKING([for LFS support])
  AC_CACHE_VAL(glibcxx_cv_LFS, [
    AC_TRY_LINK(
      [#include <unistd.h>
       #include <stdio.h>
       #include <sys/stat.h>
      ],
      [FILE* fp;
       fopen64("t", "w");
       fseeko64(fp, 0, SEEK_CUR);
       ftello64(fp);
       lseek64(1, 0, SEEK_CUR);
       struct stat64 buf;
       fstat64(1, &buf);],
      [glibcxx_cv_LFS=yes],
      [glibcxx_cv_LFS=no])
  ])
  if test $glibcxx_cv_LFS = yes; then
    AC_DEFINE(_GLIBCXX_USE_LFS, 1, [Define if LFS support is available.])
  fi
  AC_MSG_RESULT($glibcxx_cv_LFS)
  CXXFLAGS="$ac_save_CXXFLAGS"
  AC_LANG_RESTORE
])


dnl
dnl Check for whether a fully dynamic basic_string implementation should
dnl be turned on, that does not put empty objects in per-process static
dnl memory (mostly useful together with shared memory allocators, see PR
dnl libstdc++/16612 for details).
dnl
dnl --enable-fully-dynamic-string defines _GLIBCXX_FULLY_DYNAMIC_STRING
dnl --disable-fully-dynamic-string leaves _GLIBCXX_FULLY_DYNAMIC_STRING undefined
dnl  +  Usage:  GLIBCXX_ENABLE_FULLY_DYNAMIC_STRING[(DEFAULT)]
dnl       Where DEFAULT is either `yes' or `no'.
dnl
AC_DEFUN([GLIBCXX_ENABLE_FULLY_DYNAMIC_STRING], [
  GLIBCXX_ENABLE(fully-dynamic-string,$1,,[do not put empty strings in per-process static memory])
  if test $enable_fully_dynamic_string = yes; then
    AC_DEFINE(_GLIBCXX_FULLY_DYNAMIC_STRING, 1,
              [Define if a fully dynamic basic_string is wanted.])
  fi
])


dnl
dnl Does any necessary configuration of the testsuite directory.  Generates
dnl the testsuite_hooks.h header.
dnl
dnl GLIBCXX_ENABLE_SYMVERS and GLIBCXX_IS_NATIVE must be done before this.
dnl
dnl Sets:
dnl  enable_abi_check 
dnl  GLIBCXX_TEST_WCHAR_T
dnl  GLIBCXX_TEST_THREAD
dnl Substs:
dnl  baseline_dir
dnl
AC_DEFUN([GLIBCXX_CONFIGURE_TESTSUITE], [
  if $GLIBCXX_IS_NATIVE ; then
    # Do checks for resource limit functions.
    GLIBCXX_CHECK_SETRLIMIT

    # Look for setenv, so that extended locale tests can be performed.
    GLIBCXX_CHECK_STDLIB_DECL_AND_LINKAGE_3(setenv)
  fi

  if $GLIBCXX_IS_NATIVE && test $is_hosted = yes &&
     test $enable_symvers != no; then
    case "$host" in
      *-*-cygwin*)
        enable_abi_check=no ;;
      *)
        enable_abi_check=yes ;;
    esac
  else
    # Only build this as native, since automake does not understand
    # CXX_FOR_BUILD.
    enable_abi_check=no
  fi
  
  # Export file names for ABI checking.
  baseline_dir="$glibcxx_srcdir/config/abi/post/${abi_baseline_pair}\$(MULTISUBDIR)"
  AC_SUBST(baseline_dir)
])


dnl
dnl Set up *_INCLUDES variables for all sundry Makefile.am's.
dnl
dnl Substs:
dnl  GLIBCXX_INCLUDES
dnl  TOPLEVEL_INCLUDES
dnl
AC_DEFUN([GLIBCXX_EXPORT_INCLUDES], [
  # Used for every C++ compile we perform.
  GLIBCXX_INCLUDES="\
-I$glibcxx_builddir/include/$host_alias \
-I$glibcxx_builddir/include \
-I$glibcxx_srcdir/libsupc++"

  # For Canadian crosses, pick this up too.
  if test $CANADIAN = yes; then
    GLIBCXX_INCLUDES="$GLIBCXX_INCLUDES -I\${includedir}"
  fi

  # Stuff in the actual top level.  Currently only used by libsupc++ to
  # get unwind* headers from the gcc dir.
  #TOPLEVEL_INCLUDES='-I$(toplevel_srcdir)/gcc -I$(toplevel_srcdir)/include'
  TOPLEVEL_INCLUDES='-I$(toplevel_srcdir)/gcc'

  # Now, export this to all the little Makefiles....
  AC_SUBST(GLIBCXX_INCLUDES)
  AC_SUBST(TOPLEVEL_INCLUDES)
])


dnl
dnl Set up *_FLAGS and *FLAGS variables for all sundry Makefile.am's.
dnl (SECTION_FLAGS is done under CHECK_COMPILER_FEATURES.)
dnl
dnl Substs:
dnl  OPTIMIZE_CXXFLAGS
dnl  WARN_FLAGS
dnl
AC_DEFUN([GLIBCXX_EXPORT_FLAGS], [
  # Optimization flags that are probably a good idea for thrill-seekers. Just
  # uncomment the lines below and make, everything else is ready to go...
  # Alternatively OPTIMIZE_CXXFLAGS can be set in configure.host.
  # OPTIMIZE_CXXFLAGS = -O3 -fstrict-aliasing -fvtable-gc
  AC_SUBST(OPTIMIZE_CXXFLAGS)

  WARN_FLAGS='-Wall -Wextra -Wwrite-strings -Wcast-qual'
  AC_SUBST(WARN_FLAGS)
])


dnl
dnl All installation directory information is determined here.
dnl
dnl Substs:
dnl  gxx_install_dir
dnl  glibcxx_prefixdir
dnl  glibcxx_toolexecdir
dnl  glibcxx_toolexeclibdir
dnl
dnl Assumes cross_compiling bits already done, and with_cross_host in
dnl particular.
dnl
dnl This logic must match gcc/configure.ac's setting of gcc_gxx_include_dir.
dnl config/gxx-include-dir.m4 must be kept consistant with this as well.
AC_DEFUN([GLIBCXX_EXPORT_INSTALL_INFO], [
  glibcxx_toolexecdir=no
  glibcxx_toolexeclibdir=no
  glibcxx_prefixdir=$prefix

  AC_MSG_CHECKING([for gxx-include-dir])
  AC_ARG_WITH([gxx-include-dir],
    AC_HELP_STRING([--with-gxx-include-dir=DIR],
                   [installation directory for include files]),
    [case "$withval" in
      yes) AC_MSG_ERROR([Missing directory for --with-gxx-include-dir]) ;;
      no)  gxx_include_dir=no ;;
      *)   gxx_include_dir=$withval ;;
     esac],
    [gxx_include_dir=no])
  AC_MSG_RESULT($gxx_include_dir)

  AC_MSG_CHECKING([for --enable-version-specific-runtime-libs])
  AC_ARG_ENABLE([version-specific-runtime-libs],
    AC_HELP_STRING([--enable-version-specific-runtime-libs],
                   [Specify that runtime libraries should be installed in a compiler-specific directory]),
    [case "$enableval" in
      yes) version_specific_libs=yes ;;
      no)  version_specific_libs=no ;;
      *)   AC_MSG_ERROR([Unknown argument to enable/disable version-specific libs]);;
     esac],
    [version_specific_libs=no])
  AC_MSG_RESULT($version_specific_libs)

  # Default case for install directory for include files.
  if test $version_specific_libs = no && test $gxx_include_dir = no; then
    gxx_include_dir='include/c++/${gcc_version}'
    if test -n "$with_cross_host" && 
       test x"$with_cross_host" != x"no"; then	
      gxx_include_dir='${prefix}/${target_alias}/'"$gxx_include_dir"
    else
      gxx_include_dir='${prefix}/'"$gxx_include_dir"
    fi
  fi

  # Version-specific runtime libs processing.
  if test $version_specific_libs = yes; then
    # Need the gcc compiler version to know where to install libraries
    # and header files if --enable-version-specific-runtime-libs option
    # is selected.  FIXME: these variables are misnamed, there are
    # no executables installed in _toolexecdir or _toolexeclibdir.
    if test x"$gxx_include_dir" = x"no"; then
      gxx_include_dir='${libdir}/gcc/${host_alias}/${gcc_version}/include/c++'
    fi
    glibcxx_toolexecdir='${libdir}/gcc/${host_alias}'
    glibcxx_toolexeclibdir='${toolexecdir}/${gcc_version}$(MULTISUBDIR)'
  fi

  # Calculate glibcxx_toolexecdir, glibcxx_toolexeclibdir
  # Install a library built with a cross compiler in tooldir, not libdir.
  if test x"$glibcxx_toolexecdir" = x"no"; then
    if test -n "$with_cross_host" &&
       test x"$with_cross_host" != x"no"; then
      glibcxx_toolexecdir='${exec_prefix}/${host_alias}'
      glibcxx_toolexeclibdir='${toolexecdir}/lib'
    else
      glibcxx_toolexecdir='${libdir}/gcc/${host_alias}'
      glibcxx_toolexeclibdir='${libdir}'
    fi
    multi_os_directory=`$CXX -print-multi-os-directory`
    case $multi_os_directory in
      .) ;; # Avoid trailing /.
      *) glibcxx_toolexeclibdir=$glibcxx_toolexeclibdir/$multi_os_directory ;;
    esac
  fi

  AC_MSG_CHECKING([for install location])
  AC_MSG_RESULT($gxx_include_dir)

  AC_SUBST(glibcxx_prefixdir)
  AC_SUBST(gxx_include_dir)
  AC_SUBST(glibcxx_toolexecdir)
  AC_SUBST(glibcxx_toolexeclibdir)
])


dnl
dnl GLIBCXX_ENABLE
dnl    (FEATURE, DEFAULT, HELP-ARG, HELP-STRING)
dnl    (FEATURE, DEFAULT, HELP-ARG, HELP-STRING, permit a|b|c)
dnl    (FEATURE, DEFAULT, HELP-ARG, HELP-STRING, SHELL-CODE-HANDLER)
dnl
dnl See docs/html/17_intro/configury.html#enable for documentation.
dnl
m4_define([GLIBCXX_ENABLE],[dnl
m4_define([_g_switch],[--enable-$1])dnl
m4_define([_g_help],[AC_HELP_STRING(_g_switch$3,[$4 @<:@default=$2@:>@])])dnl
 AC_ARG_ENABLE($1,_g_help,
  m4_bmatch([$5],
   [^permit ],
     [[
      case "$enableval" in
       m4_bpatsubst([$5],[permit ])) ;;
       *) AC_MSG_ERROR(Unknown argument to enable/disable $1) ;;
          dnl Idea for future:  generate a URL pointing to
          dnl "onlinedocs/configopts.html#whatever"
      esac
     ]],
   [^$],
     [[
      case "$enableval" in
       yes|no) ;;
       *) AC_MSG_ERROR(Argument to enable/disable $1 must be yes or no) ;;
      esac
     ]],
   [[$5]]),
  [enable_]m4_bpatsubst([$1],-,_)[=][$2])
m4_undefine([_g_switch])dnl
m4_undefine([_g_help])dnl
])


dnl
dnl Check for ISO/IEC 9899:1999 "C99" support.
dnl
dnl --enable-c99 defines _GLIBCXX_USE_C99
dnl --disable-c99 leaves _GLIBCXX_USE_C99 undefined
dnl  +  Usage:  GLIBCXX_ENABLE_C99[(DEFAULT)]
dnl       Where DEFAULT is either `yes' or `no'.
dnl  +  If 'C99' stuff is not available, ignores DEFAULT and sets `no'.
dnl
AC_DEFUN([GLIBCXX_ENABLE_C99], [
  GLIBCXX_ENABLE(c99,$1,,[turns on ISO/IEC 9899:1999 support])

  if test x"$enable_c99" = x"yes"; then

  AC_LANG_SAVE
  AC_LANG_CPLUSPLUS

  # Check for the existence of <math.h> functions used if C99 is enabled.
  AC_MSG_CHECKING([for ISO C99 support in <math.h>])
  AC_CACHE_VAL(ac_c99_math, [
  AC_TRY_COMPILE([#include <math.h>],
	         [fpclassify(0.0);
	          isfinite(0.0); 
		  isinf(0.0);
	          isnan(0.0);
		  isnormal(0.0);
	  	  signbit(0.0);
	 	  isgreater(0.0,0.0);
		  isgreaterequal(0.0,0.0);
		  isless(0.0,0.0);
		  islessequal(0.0,0.0);
		  islessgreater(0.0,0.0);
		  islessgreater(0.0,0.0);
		  isunordered(0.0,0.0);
		 ],[ac_c99_math=yes], [ac_c99_math=no])
  ])
  AC_MSG_RESULT($ac_c99_math)
  if test x"$ac_c99_math" = x"yes"; then
    AC_DEFINE(_GLIBCXX_USE_C99_MATH, 1,
              [Define if C99 functions or macros in <math.h> should be imported
              in <cmath> in namespace std.])
  fi

  # Check for the existence of <complex.h> complex math functions.
  # This is necessary even though libstdc++ uses the builtin versions
  # of these functions, because if the builtin cannot be used, a reference
  # to the library function is emitted.
  AC_CHECK_HEADERS(complex.h, ac_has_complex_h=yes, ac_has_complex_h=no)
  ac_c99_complex=no;
  if test x"$ac_has_complex_h" = x"yes"; then
    AC_MSG_CHECKING([for ISO C99 support in <complex.h>])
    AC_TRY_COMPILE([#include <complex.h>],
	           [typedef __complex__ float float_type; float_type tmpf;
	            cabsf(tmpf);
		    cargf(tmpf);
		    ccosf(tmpf);
  		    ccoshf(tmpf);
		    cexpf(tmpf);
	            clogf(tmpf);
		    csinf(tmpf);
		    csinhf(tmpf);
		    csqrtf(tmpf);
		    ctanf(tmpf);
		    ctanhf(tmpf);
		    cpowf(tmpf, tmpf);
		    typedef __complex__ double double_type; double_type tmpd;
	            cabs(tmpd);
		    carg(tmpd);
		    ccos(tmpd);
  		    ccosh(tmpd);
		    cexp(tmpd);
	            clog(tmpd);
		    csin(tmpd);
		    csinh(tmpd);
		    csqrt(tmpd);
		    ctan(tmpd);
		    ctanh(tmpd);
		    cpow(tmpd, tmpd);
		    typedef __complex__ long double ld_type; ld_type tmpld;
	            cabsl(tmpld);
		    cargl(tmpld);
		    ccosl(tmpld);
  		    ccoshl(tmpld);
		    cexpl(tmpld);
	            clogl(tmpld);
		    csinl(tmpld);
		    csinhl(tmpld);
		    csqrtl(tmpld);
		    ctanl(tmpld);
		    ctanhl(tmpld);
		    cpowl(tmpld, tmpld);
		   ],[ac_c99_complex=yes], [ac_c99_complex=no])
  fi
  AC_MSG_RESULT($ac_c99_complex)
  if test x"$ac_c99_complex" = x"yes"; then
    AC_DEFINE(_GLIBCXX_USE_C99_COMPLEX, 1,
              [Define if C99 functions in <complex.h> should be used in
              <complex>. Using compiler builtins for these functions requires
              corresponding C99 library functions to be present.])
  fi

  # Check for the existence in <stdio.h> of vscanf, et. al.
  AC_MSG_CHECKING([for ISO C99 support in <stdio.h>])
  AC_CACHE_VAL(ac_c99_stdio, [
  AC_TRY_COMPILE([#include <stdio.h>
		  #include <stdarg.h>
                  void foo(char* fmt, ...)
                  {
	            va_list args; va_start(args, fmt);
                    vfscanf(stderr, "%i", args); 
		    vscanf("%i", args);
                    vsnprintf(fmt, 0, "%i", args);
                    vsscanf(fmt, "%i", args);
		  }],
                 [snprintf("12", 0, "%i");],
		 [ac_c99_stdio=yes], [ac_c99_stdio=no])
  ])
  AC_MSG_RESULT($ac_c99_stdio)

  # Check for the existence in <stdlib.h> of lldiv_t, et. al.
  AC_MSG_CHECKING([for ISO C99 support in <stdlib.h>])
  AC_CACHE_VAL(ac_c99_stdlib, [
  AC_TRY_COMPILE([#include <stdlib.h>],
                 [char* tmp;
	    	  strtof("gnu", &tmp);
		  strtold("gnu", &tmp);
	          strtoll("gnu", &tmp, 10);
	          strtoull("gnu", &tmp, 10);
	          llabs(10);
		  lldiv(10,1);
		  atoll("10");
		  _Exit(0);
		  lldiv_t mydivt;],[ac_c99_stdlib=yes], [ac_c99_stdlib=no])
  ])
  AC_MSG_RESULT($ac_c99_stdlib)

  # Check for the existence in <wchar.h> of wcstold, etc.
  ac_c99_wchar=no;
  if test x"$ac_has_wchar_h" = xyes &&
     test x"$ac_has_wctype_h" = xyes; then
    AC_MSG_CHECKING([for ISO C99 support in <wchar.h>])	
    AC_TRY_COMPILE([#include <wchar.h>
                    namespace test
                    {
		      using ::wcstold;
		      using ::wcstoll;
		      using ::wcstoull;
		    }
		   ],[],[ac_c99_wchar=yes], [ac_c99_wchar=no])

    # Checks for wide character functions that may not be present.
    # Injection of these is wrapped with guard macros.
    # NB: only put functions here, instead of immediately above, if
    # absolutely necessary.
    AC_TRY_COMPILE([#include <wchar.h>
                    namespace test { using ::vfwscanf; } ], [],
 	    	   [AC_DEFINE(HAVE_VFWSCANF,1,
			[Defined if vfwscanf exists.])],[])

    AC_TRY_COMPILE([#include <wchar.h>
                    namespace test { using ::vswscanf; } ], [],
 	    	   [AC_DEFINE(HAVE_VSWSCANF,1,
			[Defined if vswscanf exists.])],[])

    AC_TRY_COMPILE([#include <wchar.h>
                    namespace test { using ::vwscanf; } ], [],
 	    	   [AC_DEFINE(HAVE_VWSCANF,1,[Defined if vwscanf exists.])],[])

    AC_TRY_COMPILE([#include <wchar.h>
                    namespace test { using ::wcstof; } ], [],
 	    	   [AC_DEFINE(HAVE_WCSTOF,1,[Defined if wcstof exists.])],[])

    AC_TRY_COMPILE([#include <wctype.h>],
                   [ wint_t t; int i = iswblank(t);], 
 	    	   [AC_DEFINE(HAVE_ISWBLANK,1,
			[Defined if iswblank exists.])],[])

    AC_MSG_RESULT($ac_c99_wchar)
  fi

  # Option parsed, now set things appropriately.
  if test x"$ac_c99_math" = x"no" ||
     test x"$ac_c99_complex" = x"no" ||
     test x"$ac_c99_stdio" = x"no" ||
     test x"$ac_c99_stdlib" = x"no" ||
     test x"$ac_c99_wchar" = x"no"; then
    enable_c99=no;
  else
    AC_DEFINE(_GLIBCXX_USE_C99, 1,
    [Define if C99 functions or macros from <wchar.h>, <math.h>,
    <complex.h>, <stdio.h>, and <stdlib.h> can be used or exposed.])
  fi

  AC_LANG_RESTORE
  fi	

  AC_MSG_CHECKING([for fully enabled ISO C99 support])
  AC_MSG_RESULT($enable_c99)
])


dnl
dnl Check for ISO/IEC 9899:1999 "C99" support to ISO/IEC DTR 19768 "TR1"
dnl facilities in Chapter 8, "C compatibility".
dnl
AC_DEFUN([GLIBCXX_CHECK_C99_TR1], [

  AC_LANG_SAVE
  AC_LANG_CPLUSPLUS

  # Check for the existence of <complex.h> complex math functions used
  # by tr1/complex.
  AC_CHECK_HEADERS(complex.h, ac_has_complex_h=yes, ac_has_complex_h=no)
  ac_c99_complex_tr1=no;
  if test x"$ac_has_complex_h" = x"yes"; then
    AC_MSG_CHECKING([for ISO C99 support to TR1 in <complex.h>])
    AC_TRY_COMPILE([#include <complex.h>],
	           [typedef __complex__ float float_type; float_type tmpf;
	            cacosf(tmpf);
	            casinf(tmpf);
	            catanf(tmpf);
	            cacoshf(tmpf);
	            casinhf(tmpf);
	            catanhf(tmpf);
		    typedef __complex__ double double_type; double_type tmpd;
	            cacos(tmpd);
	            casin(tmpd);
	            catan(tmpd);
	            cacosh(tmpd);
	            casinh(tmpd);
	            catanh(tmpd);
		    typedef __complex__ long double ld_type; ld_type tmpld;
	            cacosl(tmpld);
	            casinl(tmpld);
	            catanl(tmpld);
	            cacoshl(tmpld);
	            casinhl(tmpld);
	            catanhl(tmpld);
		   ],[ac_c99_complex_tr1=yes], [ac_c99_complex_tr1=no])
  fi
  AC_MSG_RESULT($ac_c99_complex_tr1)
  if test x"$ac_c99_complex_tr1" = x"yes"; then
    AC_DEFINE(_GLIBCXX_USE_C99_COMPLEX_TR1, 1,
              [Define if C99 functions in <complex.h> should be used in
              <tr1/complex>. Using compiler builtins for these functions
	      requires corresponding C99 library functions to be present.])
  fi

  # Check for the existence of <ctype.h> functions.
  AC_MSG_CHECKING([for ISO C99 support to TR1 in <ctype.h>])
  AC_CACHE_VAL(ac_c99_ctype_tr1, [
  AC_TRY_COMPILE([#include <ctype.h>],
	         [int ch;
	          int ret;
	          ret = isblank(ch);
		 ],[ac_c99_ctype_tr1=yes], [ac_c99_ctype_tr1=no])
  ])
  AC_MSG_RESULT($ac_c99_ctype_tr1)
  if test x"$ac_c99_ctype_tr1" = x"yes"; then
    AC_DEFINE(_GLIBCXX_USE_C99_CTYPE_TR1, 1,
              [Define if C99 functions in <ctype.h> should be imported in
	      <tr1/cctype> in namespace std::tr1.])
  fi

  # Check for the existence of <fenv.h> functions.
  AC_CHECK_HEADERS(fenv.h, ac_has_fenv_h=yes, ac_has_fenv_h=no)
  ac_c99_fenv_tr1=no;
  if test x"$ac_has_fenv_h" = x"yes"; then
    AC_MSG_CHECKING([for ISO C99 support to TR1 in <fenv.h>])
    AC_TRY_COMPILE([#include <fenv.h>],
	           [int except, mode;
	            fexcept_t* pflag;
                    fenv_t* penv;
	            int ret;
	            ret = feclearexcept(except);
	            ret = fegetexceptflag(pflag, except);
	            ret = feraiseexcept(except);
	            ret = fesetexceptflag(pflag, except);
	            ret = fetestexcept(except);
	            ret = fegetround();
	            ret = fesetround(mode);
	            ret = fegetenv(penv);
	            ret = feholdexcept(penv);
	            ret = fesetenv(penv);
	            ret = feupdateenv(penv);
		   ],[ac_c99_fenv_tr1=yes], [ac_c99_fenv_tr1=no])
  fi
  AC_MSG_RESULT($ac_c99_fenv_tr1)
  if test x"$ac_c99_fenv_tr1" = x"yes"; then
    AC_DEFINE(_GLIBCXX_USE_C99_FENV_TR1, 1,
              [Define if C99 functions in <fenv.h> should be imported in
	      <tr1/cfenv> in namespace std::tr1.])
  fi

  # Check for the existence of <stdint.h> types.
  AC_MSG_CHECKING([for ISO C99 support to TR1 in <stdint.h>])
  AC_CACHE_VAL(ac_c99_stdint_tr1, [
  AC_TRY_COMPILE([#include <stdint.h>],
	         [typedef int8_t          my_int8_t;
	          typedef int16_t         my_int16_t;
	          typedef int32_t         my_int32_t;
	          typedef int64_t         my_int64_t;
	          typedef int_fast8_t     my_int_fast8_t;
	          typedef int_fast16_t    my_int_fast16_t;
	          typedef int_fast32_t    my_int_fast32_t;
	          typedef int_fast64_t    my_int_fast64_t;	
	          typedef int_least8_t    my_int_least8_t;
	          typedef int_least16_t   my_int_least16_t;
	          typedef int_least32_t   my_int_least32_t;
	          typedef int_least64_t   my_int_least64_t;
		  typedef intmax_t        my_intmax_t;
		  typedef intptr_t        my_intptr_t;
	          typedef uint8_t         my_uint8_t;
	          typedef uint16_t        my_uint16_t;
	          typedef uint32_t        my_uint32_t;
	          typedef uint64_t        my_uint64_t;
	          typedef uint_fast8_t    my_uint_fast8_t;
	          typedef uint_fast16_t   my_uint_fast16_t;
	          typedef uint_fast32_t   my_uint_fast32_t;
	          typedef uint_fast64_t   my_uint_fast64_t;	
	          typedef uint_least8_t   my_uint_least8_t;
	          typedef uint_least16_t  my_uint_least16_t;
	          typedef uint_least32_t  my_uint_least32_t;
	          typedef uint_least64_t  my_uint_least64_t;
		  typedef uintmax_t       my_uintmax_t;
		  typedef uintptr_t       my_uintptr_t;
		 ],[ac_c99_stdint_tr1=yes], [ac_c99_stdint_tr1=no])
  ])
  AC_MSG_RESULT($ac_c99_stdint_tr1)
  if test x"$ac_c99_stdint_tr1" = x"yes"; then
    AC_DEFINE(_GLIBCXX_USE_C99_STDINT_TR1, 1,
              [Define if C99 types in <stdint.h> should be imported in
	      <tr1/cstdint> in namespace std::tr1.])
  fi

  # Check for the existence of <math.h> functions.
  AC_MSG_CHECKING([for ISO C99 support to TR1 in <math.h>])
  AC_CACHE_VAL(ac_c99_math_tr1, [
  AC_TRY_COMPILE([#include <math.h>],
	         [typedef double_t  my_double_t;
	          typedef float_t   my_float_t;
	          acosh(0.0);
	          acoshf(0.0f);
	          acoshl(0.0l);
	          asinh(0.0);
	          asinhf(0.0f);
	          asinhl(0.0l);
	          atanh(0.0);
	          atanhf(0.0f);
	          atanhl(0.0l);
	          cbrt(0.0);
	          cbrtf(0.0f);
	          cbrtl(0.0l);
	          copysign(0.0, 0.0);
	          copysignf(0.0f, 0.0f);
	          copysignl(0.0l, 0.0l);
	          erf(0.0);
	          erff(0.0f);
	          erfl(0.0l);
	          erfc(0.0);
	          erfcf(0.0f);
	          erfcl(0.0l);
	          exp2(0.0);
	          exp2f(0.0f);
	          exp2l(0.0l);
	          expm1(0.0);
	          expm1f(0.0f);
	          expm1l(0.0l);
	          fdim(0.0, 0.0);
	          fdimf(0.0f, 0.0f);
	          fdiml(0.0l, 0.0l);
	          fma(0.0, 0.0, 0.0);
	          fmaf(0.0f, 0.0f, 0.0f);
	          fmal(0.0l, 0.0l, 0.0l);
	          fmax(0.0, 0.0);
	          fmaxf(0.0f, 0.0f);
	          fmaxl(0.0l, 0.0l);
	          fmin(0.0, 0.0);
	          fminf(0.0f, 0.0f);
	          fminl(0.0l, 0.0l);
	          hypot(0.0, 0.0);
	          hypotf(0.0f, 0.0f);
	          hypotl(0.0l, 0.0l);
	          ilogb(0.0);
	          ilogbf(0.0f);
	          ilogbl(0.0l);
	          lgamma(0.0);
	          lgammaf(0.0f);
	          lgammal(0.0l);
	          llrint(0.0);
	          llrintf(0.0f);
	          llrintl(0.0l);
	          llround(0.0);
	          llroundf(0.0f);
	          llroundl(0.0l);
	          log1p(0.0);
	          log1pf(0.0f);
	          log1pl(0.0l);
	          log2(0.0);
	          log2f(0.0f);
	          log2l(0.0l);
	          logb(0.0);
	          logbf(0.0f);
	          logbl(0.0l);
	          lrint(0.0);
	          lrintf(0.0f);
	          lrintl(0.0l);
	          lround(0.0);
	          lroundf(0.0f);
	          lroundl(0.0l);
	          nan(0);
	          nanf(0);
	          nanl(0);
	          nearbyint(0.0);
	          nearbyintf(0.0f);
	          nearbyintl(0.0l);
	          nextafter(0.0, 0.0);
	          nextafterf(0.0f, 0.0f);
	          nextafterl(0.0l, 0.0l);
	          nexttoward(0.0, 0.0);
	          nexttowardf(0.0f, 0.0f);
	          nexttowardl(0.0l, 0.0l);
	          remainder(0.0, 0.0);
	          remainderf(0.0f, 0.0f);
	          remainderl(0.0l, 0.0l);
	          remquo(0.0, 0.0, 0);
	          remquo(0.0f, 0.0f, 0);
	          remquo(0.0l, 0.0l, 0);
	          rint(0.0);
	          rintf(0.0f);
	          rintl(0.0l);
	          round(0.0);
	          roundf(0.0f);
	          roundl(0.0l);
	          scalbln(0.0, 0l);
	          scalblnf(0.0f, 0l);
	          scalblnl(0.0l, 0l);
	          scalbn(0.0, 0);
	          scalbnf(0.0f, 0);
	          scalbnl(0.0l, 0);
	          tgamma(0.0);
	          tgammaf(0.0f);
	          tgammal(0.0l);
	          trunc(0.0);
	          truncf(0.0f);
	          truncl(0.0l);
		 ],[ac_c99_math_tr1=yes], [ac_c99_math_tr1=no])
  ])
  AC_MSG_RESULT($ac_c99_math_tr1)
  if test x"$ac_c99_math_tr1" = x"yes"; then
    AC_DEFINE(_GLIBCXX_USE_C99_MATH_TR1, 1,
              [Define if C99 functions or macros in <math.h> should be imported
              in <tr1/cmath> in namespace std::tr1.])
  fi

  # Check for the existence of <inttypes.h> functions (NB: doesn't make
  # sense if the previous check fails, per C99, 7.8/1).
  ac_c99_inttypes_tr1=no;
  if test x"$ac_c99_stdint_tr1" = x"yes"; then
    AC_MSG_CHECKING([for ISO C99 support to TR1 in <inttypes.h>])
    AC_TRY_COMPILE([#include <inttypes.h>],
	           [intmax_t i, numer, denom, base;
	            const char* s;
	            char** endptr;
	            intmax_t ret = imaxabs(i);
	            imaxdiv_t dret = imaxdiv(numer, denom);
	            ret = strtoimax(s, endptr, base);
	            uintmax_t uret = strtoumax(s, endptr, base);
        	   ],[ac_c99_inttypes_tr1=yes], [ac_c99_inttypes_tr1=no])
  fi
  AC_MSG_RESULT($ac_c99_inttypes_tr1)
  if test x"$ac_c99_inttypes_tr1" = x"yes"; then
    AC_DEFINE(_GLIBCXX_USE_C99_INTTYPES_TR1, 1,
              [Define if C99 functions in <inttypes.h> should be imported in
              <tr1/cinttypes> in namespace std::tr1.])
  fi

  # Check for the existence of the <stdbool.h> header.	
  AC_CHECK_HEADERS(stdbool.h)

  AC_LANG_RESTORE
])

dnl
dnl Check whether "dev/random" and "dev/urandom" are available for the
dnl random_device of "TR1" (Chapter 5.1, "Random number generation").
dnl
AC_DEFUN([GLIBCXX_CHECK_RANDOM_TR1], [

  AC_MSG_CHECKING([for "dev/random" and "dev/urandom" for TR1 random_device])
  AC_CACHE_VAL(ac_random_tr1, [
  AC_TRY_RUN([#include <stdio.h>
	      int main()
	      {
                return !(fopen("/dev/random", "r")
                         && fopen("/dev/urandom", "r"));
	      }	      
	     ],
             [ac_random_tr1=yes], [ac_random_tr1=no],
	     [ac_random_tr1=no])
  ])
  AC_MSG_RESULT($ac_random_tr1)
  if test x"$ac_random_tr1" = x"yes"; then
    AC_DEFINE(_GLIBCXX_USE_RANDOM_TR1, 1,
              [Define if dev/random and dev/urandom are available for
	       the random_device of TR1 (Chapter 5.1).])
  fi

])

dnl
dnl Check for what type of C headers to use.
dnl
dnl --enable-cheaders= [does stuff].
dnl --disable-cheaders [does not do anything, really].
dnl  +  Usage:  GLIBCXX_ENABLE_CHEADERS[(DEFAULT)]
dnl       Where DEFAULT is either `c' or `c_std'.
dnl
AC_DEFUN([GLIBCXX_ENABLE_CHEADERS], [
  GLIBCXX_ENABLE(cheaders,$1,[=KIND],
    [construct "C" headers for g++], [permit c|c_std])
  AC_MSG_NOTICE("C" header strategy set to $enable_cheaders)

  C_INCLUDE_DIR='${glibcxx_srcdir}/include/'$enable_cheaders

  AC_SUBST(C_INCLUDE_DIR)
  GLIBCXX_CONDITIONAL(GLIBCXX_C_HEADERS_C, test $enable_cheaders = c)
  GLIBCXX_CONDITIONAL(GLIBCXX_C_HEADERS_C_STD, test $enable_cheaders = c_std)
  GLIBCXX_CONDITIONAL(GLIBCXX_C_HEADERS_COMPATIBILITY, test $c_compatibility = yes)
])


dnl
dnl Check for which locale library to use.  The choice is mapped to
dnl a subdirectory of config/locale.
dnl
dnl Default is generic.
dnl
AC_DEFUN([GLIBCXX_ENABLE_CLOCALE], [
  AC_MSG_CHECKING([for C locale to use])
  GLIBCXX_ENABLE(clocale,auto,[@<:@=MODEL@:>@],
    [use MODEL for target locale package],
    [permit generic|gnu|ieee_1003.1-2001|yes|no|auto])
  
  # If they didn't use this option switch, or if they specified --enable
  # with no specific model, we'll have to look for one.  If they
  # specified --disable (???), do likewise.
  if test $enable_clocale = no || test $enable_clocale = yes; then
     enable_clocale=auto
  fi

  # Either a known package, or "auto"
  enable_clocale_flag=$enable_clocale

  # Probe for locale support if no specific model is specified.
  # Default to "generic".
  if test $enable_clocale_flag = auto; then
    case ${target_os} in
      linux* | gnu* | kfreebsd*-gnu | knetbsd*-gnu)
        AC_EGREP_CPP([_GLIBCXX_ok], [
        #include <features.h>
        #if __GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 2)
          _GLIBCXX_ok
        #endif
        ], enable_clocale_flag=gnu, enable_clocale_flag=generic)

        # Test for bugs early in glibc-2.2.x series
          if test $enable_clocale_flag = gnu; then
          AC_TRY_RUN([
          #define _GNU_SOURCE 1
          #include <locale.h>
          #include <string.h>
          #if __GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ > 2)
          extern __typeof(newlocale) __newlocale;
          extern __typeof(duplocale) __duplocale;
          extern __typeof(strcoll_l) __strcoll_l;
          #endif
          int main()
          {
              const char __one[] = "Äuglein Augmen";
              const char __two[] = "Äuglein";
              int i;
              int j;
              __locale_t        loc;
               __locale_t        loc_dup;
              loc = __newlocale(1 << LC_ALL, "de_DE", 0);
              loc_dup = __duplocale(loc);
              i = __strcoll_l(__one, __two, loc);
              j = __strcoll_l(__one, __two, loc_dup);
              return 0;
          }
          ],
          [enable_clocale_flag=gnu],[enable_clocale_flag=generic],
          [enable_clocale_flag=generic])
          fi

        # ... at some point put __strxfrm_l tests in as well.
        ;;
      darwin* | freebsd*)
        enable_clocale_flag=darwin
	;;
      *)
        enable_clocale_flag=generic
        ;;
    esac
  fi

  # Deal with gettext issues.  Default to not using it (=no) until we detect
  # support for it later.  Let the user turn it off via --e/d, but let that
  # default to on for easier handling.
  USE_NLS=no
  AC_ARG_ENABLE(nls,
    AC_HELP_STRING([--enable-nls],[use Native Language Support (default)]),
    [],
    [enable_nls=yes])

  # Set configure bits for specified locale package
  case ${enable_clocale_flag} in
    generic)
      AC_MSG_RESULT(generic)

      CLOCALE_H=config/locale/generic/c_locale.h
      CLOCALE_CC=config/locale/generic/c_locale.cc
      CCODECVT_CC=config/locale/generic/codecvt_members.cc
      CCOLLATE_CC=config/locale/generic/collate_members.cc
      CCTYPE_CC=config/locale/generic/ctype_members.cc
      CMESSAGES_H=config/locale/generic/messages_members.h
      CMESSAGES_CC=config/locale/generic/messages_members.cc
      CMONEY_CC=config/locale/generic/monetary_members.cc
      CNUMERIC_CC=config/locale/generic/numeric_members.cc
      CTIME_H=config/locale/generic/time_members.h
      CTIME_CC=config/locale/generic/time_members.cc
      CLOCALE_INTERNAL_H=config/locale/generic/c++locale_internal.h
      ;;
    darwin)
      AC_MSG_RESULT(darwin or freebsd)

      CLOCALE_H=config/locale/generic/c_locale.h
      CLOCALE_CC=config/locale/generic/c_locale.cc
      CCODECVT_CC=config/locale/generic/codecvt_members.cc
      CCOLLATE_CC=config/locale/generic/collate_members.cc
      CCTYPE_CC=config/locale/darwin/ctype_members.cc
      CMESSAGES_H=config/locale/generic/messages_members.h
      CMESSAGES_CC=config/locale/generic/messages_members.cc
      CMONEY_CC=config/locale/generic/monetary_members.cc
      CNUMERIC_CC=config/locale/generic/numeric_members.cc
      CTIME_H=config/locale/generic/time_members.h
      CTIME_CC=config/locale/generic/time_members.cc
      CLOCALE_INTERNAL_H=config/locale/generic/c++locale_internal.h
      ;;
	
    gnu)
      AC_MSG_RESULT(gnu)

      # Declare intention to use gettext, and add support for specific
      # languages.
      # For some reason, ALL_LINGUAS has to be before AM-GNU-GETTEXT
      ALL_LINGUAS="de fr"

      # Don't call AM-GNU-GETTEXT here. Instead, assume glibc.
      AC_CHECK_PROG(check_msgfmt, msgfmt, yes, no)
      if test x"$check_msgfmt" = x"yes" && test x"$enable_nls" = x"yes"; then
        USE_NLS=yes
      fi
      # Export the build objects.
      for ling in $ALL_LINGUAS; do \
        glibcxx_MOFILES="$glibcxx_MOFILES $ling.mo"; \
        glibcxx_POFILES="$glibcxx_POFILES $ling.po"; \
      done
      AC_SUBST(glibcxx_MOFILES)
      AC_SUBST(glibcxx_POFILES)

      CLOCALE_H=config/locale/gnu/c_locale.h
      CLOCALE_CC=config/locale/gnu/c_locale.cc
      CCODECVT_CC=config/locale/gnu/codecvt_members.cc
      CCOLLATE_CC=config/locale/gnu/collate_members.cc
      CCTYPE_CC=config/locale/gnu/ctype_members.cc
      CMESSAGES_H=config/locale/gnu/messages_members.h
      CMESSAGES_CC=config/locale/gnu/messages_members.cc
      CMONEY_CC=config/locale/gnu/monetary_members.cc
      CNUMERIC_CC=config/locale/gnu/numeric_members.cc
      CTIME_H=config/locale/gnu/time_members.h
      CTIME_CC=config/locale/gnu/time_members.cc
      CLOCALE_INTERNAL_H=config/locale/gnu/c++locale_internal.h
      ;;
    ieee_1003.1-2001)
      AC_MSG_RESULT(IEEE 1003.1)

      CLOCALE_H=config/locale/ieee_1003.1-2001/c_locale.h
      CLOCALE_CC=config/locale/ieee_1003.1-2001/c_locale.cc
      CCODECVT_CC=config/locale/generic/codecvt_members.cc
      CCOLLATE_CC=config/locale/generic/collate_members.cc
      CCTYPE_CC=config/locale/generic/ctype_members.cc
      CMESSAGES_H=config/locale/ieee_1003.1-2001/messages_members.h
      CMESSAGES_CC=config/locale/ieee_1003.1-2001/messages_members.cc
      CMONEY_CC=config/locale/generic/monetary_members.cc
      CNUMERIC_CC=config/locale/generic/numeric_members.cc
      CTIME_H=config/locale/generic/time_members.h
      CTIME_CC=config/locale/generic/time_members.cc
      CLOCALE_INTERNAL_H=config/locale/generic/c++locale_internal.h
      ;;
  esac

  # This is where the testsuite looks for locale catalogs, using the
  # -DLOCALEDIR define during testsuite compilation.
  glibcxx_localedir=${glibcxx_builddir}/po/share/locale
  AC_SUBST(glibcxx_localedir)

  # A standalone libintl (e.g., GNU libintl) may be in use.
  if test $USE_NLS = yes; then
    AC_CHECK_HEADERS([libintl.h], [], USE_NLS=no)
    AC_SEARCH_LIBS(gettext, intl, [], USE_NLS=no)
  fi
  if test $USE_NLS = yes; then
    AC_DEFINE(_GLIBCXX_USE_NLS, 1, 
              [Define if NLS translations are to be used.])
  fi

  AC_SUBST(USE_NLS)
  AC_SUBST(CLOCALE_H)
  AC_SUBST(CMESSAGES_H)
  AC_SUBST(CCODECVT_CC)
  AC_SUBST(CCOLLATE_CC)
  AC_SUBST(CCTYPE_CC)
  AC_SUBST(CMESSAGES_CC)
  AC_SUBST(CMONEY_CC)
  AC_SUBST(CNUMERIC_CC)
  AC_SUBST(CTIME_H)
  AC_SUBST(CTIME_CC)
  AC_SUBST(CLOCALE_CC)
  AC_SUBST(CLOCALE_INTERNAL_H)
])


dnl
dnl Check for which std::allocator base class to use.  The choice is
dnl mapped from a subdirectory of include/ext.
dnl
dnl Default is new.
dnl
AC_DEFUN([GLIBCXX_ENABLE_ALLOCATOR], [
  AC_MSG_CHECKING([for std::allocator base class])
  GLIBCXX_ENABLE(libstdcxx-allocator,auto,[=KIND],
    [use KIND for target std::allocator base],
    [permit new|malloc|mt|bitmap|pool|yes|no|auto])

  # If they didn't use this option switch, or if they specified --enable
  # with no specific model, we'll have to look for one.  If they
  # specified --disable (???), do likewise.
  if test $enable_libstdcxx_allocator = no ||
     test $enable_libstdcxx_allocator = yes;
  then
     enable_libstdcxx_allocator=auto
  fi

  # Either a known package, or "auto". Auto implies the default choice
  # for a particular platform.
  enable_libstdcxx_allocator_flag=$enable_libstdcxx_allocator

  # Probe for host-specific support if no specific model is specified.
  # Default to "new".
  if test $enable_libstdcxx_allocator_flag = auto; then
    case ${target_os} in
      linux* | gnu* | kfreebsd*-gnu | knetbsd*-gnu)
        enable_libstdcxx_allocator_flag=new
        ;;
      *)
        enable_libstdcxx_allocator_flag=new
        ;;
    esac
  fi
  AC_MSG_RESULT($enable_libstdcxx_allocator_flag)
  

  # Set configure bits for specified locale package
  case ${enable_libstdcxx_allocator_flag} in
    bitmap)
      ALLOCATOR_H=config/allocator/bitmap_allocator_base.h
      ALLOCATOR_NAME=__gnu_cxx::bitmap_allocator
      ;;
    malloc)
      ALLOCATOR_H=config/allocator/malloc_allocator_base.h
      ALLOCATOR_NAME=__gnu_cxx::malloc_allocator
      ;;
    mt)
      ALLOCATOR_H=config/allocator/mt_allocator_base.h
      ALLOCATOR_NAME=__gnu_cxx::__mt_alloc
      ;;
    new)
      ALLOCATOR_H=config/allocator/new_allocator_base.h
      ALLOCATOR_NAME=__gnu_cxx::new_allocator
      ;;
    pool)
      ALLOCATOR_H=config/allocator/pool_allocator_base.h
      ALLOCATOR_NAME=__gnu_cxx::__pool_alloc
      ;;	
  esac

  AC_SUBST(ALLOCATOR_H)
  AC_SUBST(ALLOCATOR_NAME)
])


dnl
dnl Check for whether the Boost-derived checks should be turned on.
dnl
dnl --enable-concept-checks turns them on.
dnl --disable-concept-checks leaves them off.
dnl  +  Usage:  GLIBCXX_ENABLE_CONCEPT_CHECKS[(DEFAULT)]
dnl       Where DEFAULT is either `yes' or `no'.
dnl
AC_DEFUN([GLIBCXX_ENABLE_CONCEPT_CHECKS], [
  GLIBCXX_ENABLE(concept-checks,$1,,[use Boost-derived template checks])
  if test $enable_concept_checks = yes; then
    AC_DEFINE(_GLIBCXX_CONCEPT_CHECKS, 1,
              [Define to use concept checking code from the boost libraries.])
  fi
])


dnl
dnl Check for which I/O library to use:  stdio, or something specific.
dnl
dnl Default is stdio.
dnl
AC_DEFUN([GLIBCXX_ENABLE_CSTDIO], [
  AC_MSG_CHECKING([for underlying I/O to use])
  GLIBCXX_ENABLE(cstdio,stdio,[=PACKAGE],
    [use target-specific I/O package], [permit stdio])

  # Now that libio has been removed, you can have any color you want as long
  # as it's black.  This is one big no-op until other packages are added, but
  # showing the framework never hurts.
  case ${enable_cstdio} in
    stdio)
      CSTDIO_H=config/io/c_io_stdio.h
      BASIC_FILE_H=config/io/basic_file_stdio.h
      BASIC_FILE_CC=config/io/basic_file_stdio.cc
      AC_MSG_RESULT(stdio)
      ;;
  esac

  AC_SUBST(CSTDIO_H)
  AC_SUBST(BASIC_FILE_H)
  AC_SUBST(BASIC_FILE_CC)
])


dnl
dnl Check for "unusual" flags to pass to the compiler while building.
dnl
dnl --enable-cxx-flags='-foo -bar -baz' is a general method for passing
dnl     experimental flags such as -fpch, -fIMI, -Dfloat=char, etc.
dnl --disable-cxx-flags passes nothing.
dnl  +  See http://gcc.gnu.org/ml/libstdc++/2000-q2/msg00131.html
dnl         http://gcc.gnu.org/ml/libstdc++/2000-q2/msg00284.html
dnl         http://gcc.gnu.org/ml/libstdc++/2000-q1/msg00035.html
dnl  +  Usage:  GLIBCXX_ENABLE_CXX_FLAGS(default flags)
dnl       If "default flags" is an empty string, the effect is the same
dnl       as --disable or --enable=no.
dnl
AC_DEFUN([GLIBCXX_ENABLE_CXX_FLAGS], [dnl
  AC_MSG_CHECKING([for extra compiler flags for building])
  GLIBCXX_ENABLE(cxx-flags,$1,[=FLAGS],
    [pass compiler FLAGS when building library],
    [case "x$enable_cxx_flags" in
      xno | x)   enable_cxx_flags= ;;
      x-*)       ;;
      *)         AC_MSG_ERROR(_g_switch needs compiler flags as arguments) ;;
     esac])

  # Run through flags (either default or command-line) and set anything
  # extra (e.g., #defines) that must accompany particular g++ options.
  if test -n "$enable_cxx_flags"; then
    for f in $enable_cxx_flags; do
      case "$f" in
        -fhonor-std)  ;;
        -*)  ;;
        *)   # and we're trying to pass /what/ exactly?
             AC_MSG_ERROR([compiler flags start with a -]) ;;
      esac
    done
  fi

  EXTRA_CXX_FLAGS="$enable_cxx_flags"
  AC_MSG_RESULT($EXTRA_CXX_FLAGS)
  AC_SUBST(EXTRA_CXX_FLAGS)
])


dnl
dnl Check to see if debugging libraries are to be built.
dnl
dnl --enable-libstdcxx-debug
dnl builds a separate set of debugging libraries in addition to the
dnl normal (shared, static) libstdc++ binaries.
dnl
dnl --disable-libstdcxx-debug
dnl builds only one (non-debug) version of libstdc++.
dnl
dnl --enable-libstdcxx-debug-flags=FLAGS
dnl iff --enable-debug == yes, then use FLAGS to build the debug library.
dnl
dnl  +  Usage:  GLIBCXX_ENABLE_DEBUG[(DEFAULT)]
dnl       Where DEFAULT is either `yes' or `no'.
dnl
AC_DEFUN([GLIBCXX_ENABLE_DEBUG], [
  AC_MSG_CHECKING([for additional debug build])
  GLIBCXX_ENABLE(libstdcxx-debug,$1,,[build extra debug library])
  AC_MSG_RESULT($enable_libstdcxx_debug)
  GLIBCXX_CONDITIONAL(GLIBCXX_BUILD_DEBUG, test $enable_libstdcxx_debug = yes)
])


dnl
dnl Check for explicit debug flags.
dnl
dnl --enable-libstdcxx-debug-flags='-O1'
dnl is a general method for passing flags to be used when
dnl building debug libraries with --enable-debug.
dnl
dnl --disable-libstdcxx-debug-flags does nothing.
dnl  +  Usage:  GLIBCXX_ENABLE_DEBUG_FLAGS(default flags)
dnl       If "default flags" is an empty string, the effect is the same
dnl       as --disable or --enable=no.
dnl
AC_DEFUN([GLIBCXX_ENABLE_DEBUG_FLAGS], [
  GLIBCXX_ENABLE(libstdcxx-debug-flags,[$1],[=FLAGS],
    [pass compiler FLAGS when building debug library],
    [case "x$enable_libstdcxx_debug_flags" in
      xno | x)    enable_libstdcxx_debug_flags= ;;
      x-*)        ;;
      *)          AC_MSG_ERROR(_g_switch needs compiler flags as arguments) ;;
     esac])

  # Option parsed, now set things appropriately
  DEBUG_FLAGS="$enable_libstdcxx_debug_flags"
  AC_SUBST(DEBUG_FLAGS)

  AC_MSG_NOTICE([Debug build flags set to $DEBUG_FLAGS])
])


dnl
dnl Check if the user only wants a freestanding library implementation.
dnl
dnl --disable-hosted-libstdcxx will turn off most of the library build,
dnl installing only the headers required by [17.4.1.3] and the language
dnl support library.  More than that will be built (to keep the Makefiles
dnl conveniently clean), but not installed.
dnl
dnl Sets:
dnl  is_hosted  (yes/no)
dnl
dnl Defines:
dnl  _GLIBCXX_HOSTED   (always defined, either to 1 or 0)
dnl
AC_DEFUN([GLIBCXX_ENABLE_HOSTED], [
  AC_ARG_ENABLE([hosted-libstdcxx],
    AC_HELP_STRING([--disable-hosted-libstdcxx],
                   [only build freestanding C++ runtime support]),,
    [case "$host" in
	arm*-*-symbianelf*) 
	    enable_hosted_libstdcxx=no
	    ;;
        *) 
	    enable_hosted_libstdcxx=yes
	    ;;
     esac])
  if test "$enable_hosted_libstdcxx" = no; then
    AC_MSG_NOTICE([Only freestanding libraries will be built])
    is_hosted=no
    hosted_define=0
    enable_abi_check=no
    enable_libstdcxx_pch=no
  else
    is_hosted=yes
    hosted_define=1
  fi
  GLIBCXX_CONDITIONAL(GLIBCXX_HOSTED, test $is_hosted = yes)
  AC_DEFINE_UNQUOTED(_GLIBCXX_HOSTED, $hosted_define,
    [Define to 1 if a full hosted library is built, or 0 if freestanding.])
])


dnl
dnl Check for template specializations for the 'long long' type.
dnl The result determines only whether 'long long' I/O is enabled; things
dnl like numeric_limits<> specializations are always available.
dnl
dnl --enable-long-long defines _GLIBCXX_USE_LONG_LONG
dnl --disable-long-long leaves _GLIBCXX_USE_LONG_LONG undefined
dnl  +  Usage:  GLIBCXX_ENABLE_LONG_LONG[(DEFAULT)]
dnl       Where DEFAULT is either `yes' or `no'.
dnl
AC_DEFUN([GLIBCXX_ENABLE_LONG_LONG], [
  GLIBCXX_ENABLE(long-long,$1,,[enable template specializations for 'long long'])
  if test $enable_long_long = yes; then
    AC_DEFINE(_GLIBCXX_USE_LONG_LONG, 1, 
              [Define if code specialized for long long should be used.])
  fi
  AC_MSG_CHECKING([for enabled long long specializations])
  AC_MSG_RESULT([$enable_long_long])
])


dnl
dnl Check for template specializations for the 'wchar_t' type.
dnl
dnl --enable-wchar_t defines _GLIBCXX_USE_WCHAR_T
dnl --disable-wchar_t leaves _GLIBCXX_USE_WCHAR_T undefined
dnl  +  Usage:  GLIBCXX_ENABLE_WCHAR_T[(DEFAULT)]
dnl       Where DEFAULT is either `yes' or `no'.
dnl
dnl Necessary support must also be present.
dnl
AC_DEFUN([GLIBCXX_ENABLE_WCHAR_T], [
  GLIBCXX_ENABLE(wchar_t,$1,,[enable template specializations for 'wchar_t'])

  # Test wchar.h for mbstate_t, which is needed for char_traits and fpos.
  AC_CHECK_HEADERS(wchar.h, ac_has_wchar_h=yes, ac_has_wchar_h=no)
  AC_MSG_CHECKING([for mbstate_t])
  AC_TRY_COMPILE([#include <wchar.h>],
  [mbstate_t teststate;],
  have_mbstate_t=yes, have_mbstate_t=no)
  AC_MSG_RESULT($have_mbstate_t)
  if test x"$have_mbstate_t" = xyes; then
    AC_DEFINE(HAVE_MBSTATE_T,1,[Define if mbstate_t exists in wchar.h.])
  fi

  # Test it always, for use in GLIBCXX_ENABLE_C99, together with
  # ac_has_wchar_h.
  AC_CHECK_HEADERS(wctype.h, ac_has_wctype_h=yes, ac_has_wctype_h=no)
  
  if test x"$enable_wchar_t" = x"yes"; then

    AC_LANG_SAVE
    AC_LANG_CPLUSPLUS
    
    if test x"$ac_has_wchar_h" = xyes &&
       test x"$ac_has_wctype_h" = xyes; then
      AC_TRY_COMPILE([#include <wchar.h>
                      #include <stddef.h>
                      wint_t i;
		      long l = WEOF;
		      long j = WCHAR_MIN;
		      long k = WCHAR_MAX;
                      namespace test
                      {
			using ::btowc;
			using ::fgetwc;
			using ::fgetws;
			using ::fputwc;
			using ::fputws;
			using ::fwide;
			using ::fwprintf; 
			using ::fwscanf;
			using ::getwc;
			using ::getwchar;
 			using ::mbrlen; 
			using ::mbrtowc; 
			using ::mbsinit; 
			using ::mbsrtowcs; 
			using ::putwc;
			using ::putwchar;
			using ::swprintf; 
			using ::swscanf; 
			using ::ungetwc;
			using ::vfwprintf; 
			using ::vswprintf; 
			using ::vwprintf; 
			using ::wcrtomb; 
			using ::wcscat; 
			using ::wcschr; 
			using ::wcscmp; 
			using ::wcscoll; 
			using ::wcscpy; 
			using ::wcscspn; 
			using ::wcsftime; 
			using ::wcslen;
			using ::wcsncat; 
			using ::wcsncmp; 
			using ::wcsncpy; 
			using ::wcspbrk;
			using ::wcsrchr; 
			using ::wcsrtombs; 
			using ::wcsspn; 
			using ::wcsstr;
			using ::wcstod; 
			using ::wcstok; 
			using ::wcstol;
			using ::wcstoul; 
			using ::wcsxfrm; 
			using ::wctob; 
			using ::wmemchr;
			using ::wmemcmp;
			using ::wmemcpy;
			using ::wmemmove;
			using ::wmemset;
			using ::wprintf; 
			using ::wscanf; 
		      }
		     ],[],[], [enable_wchar_t=no])
    else
      enable_wchar_t=no
    fi

    AC_LANG_RESTORE
  fi

  if test x"$enable_wchar_t" = x"yes"; then
    AC_DEFINE(_GLIBCXX_USE_WCHAR_T, 1,
              [Define if code specialized for wchar_t should be used.])
  fi

  AC_MSG_CHECKING([for enabled wchar_t specializations])
  AC_MSG_RESULT([$enable_wchar_t])
])


dnl
dnl Check to see if building and using a C++ precompiled header can be done.
dnl
dnl --enable-libstdcxx-pch=yes
dnl default, this shows intent to use stdc++.h.gch If it looks like it
dnl may work, after some light-hearted attempts to puzzle out compiler
dnl support, flip bits on in include/Makefile.am
dnl
dnl --disable-libstdcxx-pch
dnl turns off attempts to use or build stdc++.h.gch.
dnl
dnl Substs:
dnl  glibcxx_PCHFLAGS
dnl
AC_DEFUN([GLIBCXX_ENABLE_PCH], [
  GLIBCXX_ENABLE(libstdcxx-pch,$1,,[build pre-compiled libstdc++ headers])
  if test $enable_libstdcxx_pch = yes; then
    AC_CACHE_CHECK([for compiler with PCH support],
      [glibcxx_cv_prog_CXX_pch],
      [ac_save_CXXFLAGS="$CXXFLAGS"
       CXXFLAGS="$CXXFLAGS -Werror -Winvalid-pch -Wno-deprecated"
       AC_LANG_SAVE
       AC_LANG_CPLUSPLUS
       echo '#include <math.h>' > conftest.h
       if $CXX $CXXFLAGS $CPPFLAGS -x c++-header conftest.h \
		          -o conftest.h.gch 1>&5 2>&1 &&
	        echo '#error "pch failed"' > conftest.h &&
          echo '#include "conftest.h"' > conftest.cc &&
	       $CXX -c $CXXFLAGS $CPPFLAGS conftest.cc 1>&5 2>&1 ;
       then
         glibcxx_cv_prog_CXX_pch=yes
       else
         glibcxx_cv_prog_CXX_pch=no
       fi
       rm -f conftest*
       CXXFLAGS=$ac_save_CXXFLAGS
       AC_LANG_RESTORE
      ])
    enable_libstdcxx_pch=$glibcxx_cv_prog_CXX_pch
  fi

  AC_MSG_CHECKING([for enabled PCH])
  AC_MSG_RESULT([$enable_libstdcxx_pch])

  GLIBCXX_CONDITIONAL(GLIBCXX_BUILD_PCH, test $enable_libstdcxx_pch = yes)
  if test $enable_libstdcxx_pch = yes; then
    glibcxx_PCHFLAGS="-include bits/stdtr1c++.h"
  else
    glibcxx_PCHFLAGS=""
  fi
  AC_SUBST(glibcxx_PCHFLAGS)
])


dnl
dnl Check for atomic builtins.
dnl See:
dnl http://gcc.gnu.org/onlinedocs/gcc/Atomic-Builtins.html#Atomic-Builtins
dnl
dnl This checks to see if the host supports the compiler-generated
dnl builtins for atomic operations. Note, this is intended to be an
dnl all-or-nothing switch, so all the atomic operations that are used
dnl should be checked.
dnl
dnl Note:
dnl libgomp and libgfortran do this with a link test, instead of an asm test.
dnl see: CHECK_SYNC_FETCH_AND_ADD
dnl
dnl Defines:
dnl  _GLIBCXX_ATOMIC_BUILTINS if the compiler on this target supports atomics.
dnl
AC_DEFUN([GLIBCXX_ENABLE_ATOMIC_BUILTINS], [
  AC_MSG_CHECKING([for atomic builtins])
  AC_LANG_SAVE
  AC_LANG_CPLUSPLUS

  # Fake what AC_TRY_COMPILE does.  XXX Look at redoing this new-style.
    cat > conftest.$ac_ext << EOF
[#]line __oline__ "configure"
int main()
{
  // NB: _Atomic_word not necessarily int. 
  typedef int atomic_type;
  atomic_type c1;
  atomic_type c2;
  const atomic_type c3(0);
  if (__sync_fetch_and_add(&c1, c2) == c3)
    {
      // Do something.
    }
   return 0;
}
EOF
    old_CXXFLAGS="$CXXFLAGS"
    CXXFLAGS=-S
    if AC_TRY_EVAL(ac_compile); then
      if grep __sync_fetch_and_add conftest.s >/dev/null 2>&1 ; then
        enable_atomic_builtins=no
      else
      AC_DEFINE(_GLIBCXX_ATOMIC_BUILTINS, 1,
        [Define if builtin atomic operations are supported on this host.])
        enable_atomic_builtins=yes
	atomicity_dir=cpu/generic/atomicity_builtins
      fi
    fi
    CXXFLAGS="$old_CXXFLAGS"
    rm -f conftest*

   # Now, if still generic, set to mutex.
  if test $atomicity_dir = "cpu/generic" ; then
	atomicity_dir=cpu/generic/atomicity_mutex
  fi
 AC_LANG_RESTORE
 AC_MSG_RESULT($enable_atomic_builtins)
])


dnl
dnl Check for exception handling support.  If an explicit enable/disable
dnl sjlj exceptions is given, we don't have to detect.  Otherwise the
dnl target may or may not support call frame exceptions.
dnl
dnl --enable-sjlj-exceptions forces the use of builtin setjmp.
dnl --disable-sjlj-exceptions forces the use of call frame unwinding.
dnl Neither one forces an attempt at detection.
dnl
dnl Defines:
dnl  _GLIBCXX_SJLJ_EXCEPTIONS if the compiler is configured for it
dnl
AC_DEFUN([GLIBCXX_ENABLE_SJLJ_EXCEPTIONS], [
  AC_MSG_CHECKING([for exception model to use])
  AC_LANG_SAVE
  AC_LANG_CPLUSPLUS
  GLIBCXX_ENABLE(sjlj-exceptions,auto,,
    [force use of builtin_setjmp for exceptions],
    [permit yes|no|auto])

  if test $enable_sjlj_exceptions = auto; then
    # Botheration.  Now we've got to detect the exception model.  Link tests
    # against libgcc.a are problematic since we've not been given proper -L
    # bits for single-tree newlib and libgloss.
    #
    # Fake what AC_TRY_COMPILE does.  XXX Look at redoing this new-style.
    cat > conftest.$ac_ext << EOF
[#]line __oline__ "configure"
struct S { ~S(); };
void bar();
void foo()
{
  S s;
  bar();
}
EOF
    old_CXXFLAGS="$CXXFLAGS"
    CXXFLAGS=-S
    if AC_TRY_EVAL(ac_compile); then
      if grep _Unwind_SjLj_Resume conftest.s >/dev/null 2>&1 ; then
        enable_sjlj_exceptions=yes
      elif grep _Unwind_Resume conftest.s >/dev/null 2>&1 ; then
        enable_sjlj_exceptions=no
      elif grep __cxa_end_cleanup conftest.s >/dev/null 2>&1 ; then
        enable_sjlj_exceptions=no
      fi
    fi
    CXXFLAGS="$old_CXXFLAGS"
    rm -f conftest*
  fi

  # This is a tad weird, for hysterical raisins.  We have to map
  # enable/disable to two different models.
  case $enable_sjlj_exceptions in
    yes)
      AC_DEFINE(_GLIBCXX_SJLJ_EXCEPTIONS, 1,
        [Define if the compiler is configured for setjmp/longjmp exceptions.])
      ac_exception_model_name=sjlj
      ;;
    no)
      ac_exception_model_name="call frame"
      ;;
    *)
      AC_MSG_ERROR([unable to detect exception model])
      ;;
  esac
 AC_LANG_RESTORE
 AC_MSG_RESULT($ac_exception_model_name)
])


dnl
dnl Allow visibility attributes to be used on namespaces, objects, etc.
dnl
dnl --enable-visibility enables attempt to use visibility attributes.
dnl --disable-visibility turns off all use of visibility attributes.
dnl  +  Usage:  GLIBCXX_ENABLE_VISIBILITY[(DEFAULT)]
dnl       Where DEFAULT is 'yes'.
dnl
AC_DEFUN([GLIBCXX_ENABLE_VISIBILITY], [
GLIBCXX_ENABLE(visibility,$1,,[enables visibility safe usage])

if test x$enable_visibility = xyes ; then
  dnl all hail libgfortran
  dnl Check whether the target supports hidden visibility.
  AC_CACHE_CHECK([whether the target supports hidden visibility],
		 have_attribute_visibility, [
  save_CFLAGS="$CFLAGS"
  CFLAGS="$CFLAGS -Werror"
  AC_TRY_COMPILE([void __attribute__((visibility("hidden"))) foo(void) { }],
		 [], have_attribute_visibility=yes,
		 have_attribute_visibility=no)
  CFLAGS="$save_CFLAGS"])
  if test $have_attribute_visibility = no; then
    enable_visibility=no
  fi
fi

GLIBCXX_CONDITIONAL(ENABLE_VISIBILITY, test $enable_visibility = yes)
AC_MSG_NOTICE([visibility supported: $enable_visibility])
])


dnl
dnl Add version tags to symbols in shared library (or not), additionally
dnl marking other symbols as private/local (or not).
dnl
dnl --enable-symvers=style adds a version script to the linker call when
dnl       creating the shared library.  The choice of version script is
dnl       controlled by 'style'.
dnl --disable-symvers does not.
dnl  +  Usage:  GLIBCXX_ENABLE_SYMVERS[(DEFAULT)]
dnl       Where DEFAULT is either 'yes' or 'no'.  Passing `yes' tries to
dnl       choose a default style based on linker characteristics.  Passing
dnl       'no' disables versioning.
dnl
AC_DEFUN([GLIBCXX_ENABLE_SYMVERS], [

GLIBCXX_ENABLE(symvers,$1,[=STYLE],
  [enables symbol versioning of the shared library],
  [permit yes|no|gnu|gnu-versioned-namespace|darwin|darwin-export])

# If we never went through the GLIBCXX_CHECK_LINKER_FEATURES macro, then we
# don't know enough about $LD to do tricks...
AC_REQUIRE([GLIBCXX_CHECK_LINKER_FEATURES])

# Turn a 'yes' into a suitable default.
if test x$enable_symvers = xyes ; then
  if test $enable_shared = no || test "x$LD" = x || test x$gcc_no_link = xyes; then
    enable_symvers=no
  else
    if test $with_gnu_ld = yes ; then
      enable_symvers=gnu
    else
      case ${target_os} in
        darwin*)
	  enable_symvers=darwin ;;
        *)
          enable_symvers=no ;;
      esac
    fi
  fi
fi

# Check to see if 'darwin' or 'darwin-export' can win.
if test x$enable_symvers = xdarwin-export ; then
    enable_symvers=darwin
fi

# Check to see if 'gnu' can win.
if test $enable_symvers = gnu || test $enable_symvers = gnu-versioned-namespace; then
  # Check to see if libgcc_s exists, indicating that shared libgcc is possible.
  AC_MSG_CHECKING([for shared libgcc])
  ac_save_CFLAGS="$CFLAGS"
  CFLAGS=' -lgcc_s'
  AC_TRY_LINK(, [return 0;], glibcxx_shared_libgcc=yes, glibcxx_shared_libgcc=no)
  CFLAGS="$ac_save_CFLAGS"
  if test $glibcxx_shared_libgcc = no; then
    cat > conftest.c <<EOF
int main (void) { return 0; }
EOF
changequote(,)dnl
    glibcxx_libgcc_s_suffix=`${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS \
			     -shared -shared-libgcc -o conftest.so \
			     conftest.c -v 2>&1 >/dev/null \
			     | sed -n 's/^.* -lgcc_s\([^ ]*\) .*$/\1/p'`
changequote([,])dnl
    rm -f conftest.c conftest.so
    if test x${glibcxx_libgcc_s_suffix+set} = xset; then
      CFLAGS=" -lgcc_s$glibcxx_libgcc_s_suffix"
      AC_TRY_LINK(, [return 0;], glibcxx_shared_libgcc=yes)
      CFLAGS="$ac_save_CFLAGS"
    fi
  fi
  AC_MSG_RESULT($glibcxx_shared_libgcc)

  # For GNU ld, we need at least this version.  The format is described in
  # GLIBCXX_CHECK_LINKER_FEATURES above.
  glibcxx_min_gnu_ld_version=21400

  # If no shared libgcc, can't win.
  if test $glibcxx_shared_libgcc != yes; then
      AC_MSG_WARN([=== You have requested GNU symbol versioning, but])
      AC_MSG_WARN([=== you are not building a shared libgcc_s.])
      AC_MSG_WARN([=== Symbol versioning will be disabled.])
      enable_symvers=no
  elif test $with_gnu_ld != yes ; then
    # just fail for now
    AC_MSG_WARN([=== You have requested GNU symbol versioning, but])
    AC_MSG_WARN([=== you are not using the GNU linker.])
    AC_MSG_WARN([=== Symbol versioning will be disabled.])
    enable_symvers=no
  elif test $glibcxx_gnu_ld_version -lt $glibcxx_min_gnu_ld_version ; then
    # The right tools, the right setup, but too old.  Fallbacks?
    AC_MSG_WARN(=== Linker version $glibcxx_gnu_ld_version is too old for)
    AC_MSG_WARN(=== full symbol versioning support in this release of GCC.)
    AC_MSG_WARN(=== You would need to upgrade your binutils to version)
    AC_MSG_WARN(=== $glibcxx_min_gnu_ld_version or later and rebuild GCC.)
    AC_MSG_WARN([=== Symbol versioning will be disabled.])
    enable_symvers=no
  fi
fi

# Everything parsed; figure out what file to use.
case $enable_symvers in
  no)
    SYMVER_FILE=config/abi/pre/none.ver
    ;;
  gnu)
    SYMVER_FILE=config/abi/pre/gnu.ver
    AC_DEFINE(_GLIBCXX_SYMVER_GNU, 1, 
              [Define to use GNU versioning in the shared library.])
    ;;
  gnu-versioned-namespace)
    SYMVER_FILE=config/abi/pre/gnu-versioned-namespace.ver
    AC_DEFINE(_GLIBCXX_SYMVER_GNU_NAMESPACE, 1, 
              [Define to use GNU namespace versioning in the shared library.])
    ;;
  darwin)
    SYMVER_FILE=config/abi/pre/gnu.ver
    AC_DEFINE(_GLIBCXX_SYMVER_DARWIN, 1, 
              [Define to use darwin versioning in the shared library.])
    ;;
esac

if test x$enable_symvers != xno ; then
  AC_DEFINE(_GLIBCXX_SYMVER, 1,
	 [Define to use symbol versioning in the shared library.])
fi

AC_SUBST(SYMVER_FILE)
AC_SUBST(port_specific_symbol_files)
GLIBCXX_CONDITIONAL(ENABLE_SYMVERS, test $enable_symvers != no)
GLIBCXX_CONDITIONAL(ENABLE_SYMVERS_GNU, test $enable_symvers = gnu)
GLIBCXX_CONDITIONAL(ENABLE_SYMVERS_GNU_NAMESPACE, test $enable_symvers = gnu-versioned-namespace)
GLIBCXX_CONDITIONAL(ENABLE_SYMVERS_DARWIN, test $enable_symvers = darwin)
AC_MSG_NOTICE(versioning on shared library symbols is $enable_symvers)

# Now, set up compatibility support, if any.
# In addition, need this to deal with std::size_t mangling in
# src/compatibility.cc.  In a perfect world, could use
# typeid(std::size_t).name()[0] to do direct substitution.
AC_MSG_CHECKING([for size_t as unsigned int])
ac_save_CFLAGS="$CFLAGS"
CFLAGS="-Werror"
AC_TRY_COMPILE(, [__SIZE_TYPE__* stp; unsigned int* uip; stp = uip;], 
	         [glibcxx_size_t_is_i=yes], [glibcxx_size_t_is_i=no])
CFLAGS=$ac_save_CFLAGS
if test "$glibcxx_size_t_is_i" = yes; then
  AC_DEFINE(_GLIBCXX_SIZE_T_IS_UINT, 1, [Define if size_t is unsigned int.])
fi
AC_MSG_RESULT([$glibcxx_size_t_is_i])

AC_MSG_CHECKING([for ptrdiff_t as int])
ac_save_CFLAGS="$CFLAGS"
CFLAGS="-Werror"
AC_TRY_COMPILE(, [__PTRDIFF_TYPE__* ptp; int* ip; ptp = ip;], 
	         [glibcxx_ptrdiff_t_is_i=yes], [glibcxx_ptrdiff_t_is_i=no])
CFLAGS=$ac_save_CFLAGS
if test "$glibcxx_ptrdiff_t_is_i" = yes; then
  AC_DEFINE(_GLIBCXX_PTRDIFF_T_IS_INT, 1, [Define if ptrdiff_t is int.])
fi
AC_MSG_RESULT([$glibcxx_ptrdiff_t_is_i])
])


dnl
dnl Setup to use the gcc gthr.h thread-specific memory and mutex model.
dnl We must stage the required headers so that they will be installed
dnl with the library (unlike libgcc, the STL implementation is provided
dnl solely within headers).  Since we must not inject random user-space
dnl macro names into user-provided C++ code, we first stage into <file>-in
dnl and process to <file> with an output command.  The reason for a two-
dnl stage process here is to correctly handle $srcdir!=$objdir without
dnl having to write complex code (the sed commands to clean the macro
dnl namespace are complex and fragile enough as it is).  We must also
dnl add a relative path so that -I- is supported properly.
dnl
dnl Substs:
dnl  glibcxx_thread_h
dnl
dnl Defines:
dnl  HAVE_GTHR_DEFAULT
dnl
AC_DEFUN([GLIBCXX_ENABLE_THREADS], [
  AC_MSG_CHECKING([for thread model used by GCC])
  target_thread_file=`$CXX -v 2>&1 | sed -n 's/^Thread model: //p'`
  AC_MSG_RESULT([$target_thread_file])

  if test $target_thread_file != single; then
    AC_DEFINE(HAVE_GTHR_DEFAULT, 1,
              [Define if gthr-default.h exists 
              (meaning that threading support is enabled).])
  fi

  glibcxx_thread_h=gthr-$target_thread_file.h

  dnl Check for __GTHREADS define.
  gthread_file=${toplevel_srcdir}/gcc/${glibcxx_thread_h}
  if grep __GTHREADS $gthread_file >/dev/null 2>&1 ; then
    enable_thread=yes
  else
   enable_thread=no
  fi

  AC_SUBST(glibcxx_thread_h)
])


# Check whether LC_MESSAGES is available in <locale.h>.
# Ulrich Drepper <drepper@cygnus.com>, 1995.
#
# This file file be copied and used freely without restrictions.  It can
# be used in projects which are not available under the GNU Public License
# but which still want to provide support for the GNU gettext functionality.
# Please note that the actual code is *not* freely available.

# serial 1
AC_DEFUN([AC_LC_MESSAGES], [
  AC_CHECK_HEADER(locale.h, [
    AC_CACHE_CHECK([for LC_MESSAGES], ac_cv_val_LC_MESSAGES,
      [AC_TRY_LINK([#include <locale.h>], [return LC_MESSAGES],
       ac_cv_val_LC_MESSAGES=yes, ac_cv_val_LC_MESSAGES=no)])
    if test $ac_cv_val_LC_MESSAGES = yes; then
      AC_DEFINE(HAVE_LC_MESSAGES, 1, 
                [Define if LC_MESSAGES is available in <locale.h>.])
    fi
  ])
])

# Macros from the top-level gcc directory.
m4_include([../config/tls.m4])