libctf: look for BSD versus GNU qsort_r signatures

We cannot just look for any declaration of qsort_r, because some
operating systems have a qsort_r that has a different prototype
but which still has a pair of pointers in the right places (the last two
args are interchanged): so use AC_LINK_IFELSE to check for both
known variants of qsort_r(), and swap their args into a consistent order
in a suitable inline function.  (The code for this is taken almost
unchanged from gnulib.)

(Now we are not using AC_LIBOBJ any more, we can use a better name for
the qsort_r replacement as well.)

libctf/
	* qsort_r.c: Rename to...
	* ctf-qsort_r.c: ... this.
	(_quicksort): Define to ctf_qsort_r.
	* ctf-decls.h (qsort_r): Remove.
	(ctf_qsort_r): Add.
	(struct ctf_qsort_arg): New, transport the real ARG and COMPAR.
	(ctf_qsort_compar_thunk): Rearrange the arguments to COMPAR.
	* Makefile.am (libctf_a_LIBADD): Remove.
	(libctf_a_SOURCES): New, add ctf-qsort_r.c.
	* ctf-archive.c (ctf_arc_write): Call ctf_qsort_r, not qsort_r.
	* ctf-create.c (ctf_update): Likewise.
	* configure.ac: Check for BSD versus GNU qsort_r signature.
	* Makefile.in: Regenerate.
	* config.h.in: Likewise.
	* configure: Likewise.

10 files changed, 236 insertions, 85 deletions

diff --git a/libctf/ChangeLog b/libctf/ChangeLog
index 01b8d8da248..c51efea8bcd 100644
--- a/libctf/ChangeLog
+++ b/libctf/ChangeLog
@@ -1,3 +1,21 @@
+2019-06-04  Nick Alcock  <nick.alcock@oracle.com>
+
+	* qsort_r.c: Rename to...
+	* ctf-qsort_r.c: ... this.
+	(_quicksort): Define to ctf_qsort_r.
+	* ctf-decls.h (qsort_r): Remove.
+	(ctf_qsort_r): Add.
+	(struct ctf_qsort_arg): New, transport the real ARG and COMPAR.
+	(ctf_qsort_compar_thunk): Rearrange the arguments to COMPAR.
+	* Makefile.am (libctf_a_LIBADD): Remove.
+	(libctf_a_SOURCES): New, add ctf-qsort_r.c.
+	* ctf-archive.c (ctf_arc_write): Call ctf_qsort_r, not qsort_r.
+	* ctf-create.c (ctf_update): Likewise.
+	* configure.ac: Check for BSD versus GNU qsort_r signature.
+	* Makefile.in: Regenerate.
+	* config.h.in: Likewise.
+	* configure: Likewise.
+
 2019-06-03  Nick Alcock  <nick.alcock@oracle.com>
 
 	* ctf-dump.c (ctf_dump_funcs): Free in the right place.
diff --git a/libctf/Makefile.am b/libctf/Makefile.am
index 49c9f5280a9..926c9919c56 100644
--- a/libctf/Makefile.am
+++ b/libctf/Makefile.am
@@ -35,4 +35,6 @@ noinst_LIBRARIES = libctf.a
 libctf_a_SOURCES = ctf-archive.c ctf-dump.c ctf-create.c ctf-decl.c ctf-error.c \
 		   ctf-hash.c ctf-labels.c ctf-lookup.c ctf-open.c ctf-open-bfd.c \
 		   ctf-subr.c ctf-types.c ctf-util.c
-libctf_a_LIBADD = $(LIBOBJS)
+if NEED_CTF_QSORT_R
+libctf_a_SOURCES += ctf-qsort_r.c
+endif
diff --git a/libctf/Makefile.in b/libctf/Makefile.in
index c2cada66167..4fea156c44e 100644
--- a/libctf/Makefile.in
+++ b/libctf/Makefile.in
@@ -104,6 +104,7 @@ POST_INSTALL = :
 NORMAL_UNINSTALL = :
 PRE_UNINSTALL = :
 POST_UNINSTALL = :
+@NEED_CTF_QSORT_R_TRUE@am__append_1 = ctf-qsort_r.c
 subdir = .
 ACLOCAL_M4 = $(top_srcdir)/aclocal.m4
 am__aclocal_m4_deps = $(top_srcdir)/../config/depstand.m4 \
@@ -128,12 +129,17 @@ am__v_AR_ = $(am__v_AR_@AM_DEFAULT_V@)
 am__v_AR_0 = @echo "  AR      " $@;
 am__v_AR_1 = 
 libctf_a_AR = $(AR) $(ARFLAGS)
-libctf_a_DEPENDENCIES = $(LIBOBJS)
+libctf_a_LIBADD =
+am__libctf_a_SOURCES_DIST = ctf-archive.c ctf-dump.c ctf-create.c \
+	ctf-decl.c ctf-error.c ctf-hash.c ctf-labels.c ctf-lookup.c \
+	ctf-open.c ctf-open-bfd.c ctf-subr.c ctf-types.c ctf-util.c \
+	ctf-qsort_r.c
+@NEED_CTF_QSORT_R_TRUE@am__objects_1 = ctf-qsort_r.$(OBJEXT)
 am_libctf_a_OBJECTS = ctf-archive.$(OBJEXT) ctf-dump.$(OBJEXT) \
 	ctf-create.$(OBJEXT) ctf-decl.$(OBJEXT) ctf-error.$(OBJEXT) \
 	ctf-hash.$(OBJEXT) ctf-labels.$(OBJEXT) ctf-lookup.$(OBJEXT) \
 	ctf-open.$(OBJEXT) ctf-open-bfd.$(OBJEXT) ctf-subr.$(OBJEXT) \
-	ctf-types.$(OBJEXT) ctf-util.$(OBJEXT)
+	ctf-types.$(OBJEXT) ctf-util.$(OBJEXT) $(am__objects_1)
 libctf_a_OBJECTS = $(am_libctf_a_OBJECTS)
 AM_V_P = $(am__v_P_@AM_V@)
 am__v_P_ = $(am__v_P_@AM_DEFAULT_V@)
@@ -164,7 +170,7 @@ am__v_CCLD_ = $(am__v_CCLD_@AM_DEFAULT_V@)
 am__v_CCLD_0 = @echo "  CCLD    " $@;
 am__v_CCLD_1 = 
 SOURCES = $(libctf_a_SOURCES)
-DIST_SOURCES = $(libctf_a_SOURCES)
+DIST_SOURCES = $(am__libctf_a_SOURCES_DIST)
 am__can_run_installinfo = \
   case $$AM_UPDATE_INFO_DIR in \
     n|no|NO) false;; \
@@ -196,7 +202,7 @@ am__DIST_COMMON = $(srcdir)/Makefile.in $(srcdir)/config.h.in \
 	$(top_srcdir)/../ar-lib $(top_srcdir)/../compile \
 	$(top_srcdir)/../depcomp $(top_srcdir)/../install-sh \
 	$(top_srcdir)/../missing $(top_srcdir)/../mkinstalldirs \
-	ChangeLog qsort_r.c
+	ChangeLog
 DISTFILES = $(DIST_COMMON) $(DIST_SOURCES) $(TEXINFOS) $(EXTRA_DIST)
 distdir = $(PACKAGE)-$(VERSION)
 top_distdir = $(distdir)
@@ -323,11 +329,10 @@ ZLIBINC = @zlibinc@
 AM_CPPFLAGS = -D_GNU_SOURCE -I$(top_srcdir) -I$(top_srcdir)/../include -I$(top_srcdir)/../bfd -I../bfd
 AM_CFLAGS = -std=gnu99 @ac_libctf_warn_cflags@ @warn@ @c_warn@ @WARN_PEDANTIC@ @WERROR@ $(ZLIBINC)
 noinst_LIBRARIES = libctf.a
-libctf_a_SOURCES = ctf-archive.c ctf-dump.c ctf-create.c ctf-decl.c ctf-error.c \
-		   ctf-hash.c ctf-labels.c ctf-lookup.c ctf-open.c ctf-open-bfd.c \
-		   ctf-subr.c ctf-types.c ctf-util.c
-
-libctf_a_LIBADD = $(LIBOBJS)
+libctf_a_SOURCES = ctf-archive.c ctf-dump.c ctf-create.c ctf-decl.c \
+	ctf-error.c ctf-hash.c ctf-labels.c ctf-lookup.c ctf-open.c \
+	ctf-open-bfd.c ctf-subr.c ctf-types.c ctf-util.c \
+	$(am__append_1)
 all: config.h
 	$(MAKE) $(AM_MAKEFLAGS) all-am
 
@@ -396,7 +401,6 @@ mostlyclean-compile:
 distclean-compile:
 	-rm -f *.tab.c
 
-@AMDEP_TRUE@@am__include@ @am__quote@$(DEPDIR)/qsort_r.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/ctf-archive.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/ctf-create.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/ctf-decl.Po@am__quote@
@@ -407,6 +411,7 @@ distclean-compile:
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/ctf-lookup.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/ctf-open-bfd.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/ctf-open.Po@am__quote@
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/ctf-qsort_r.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/ctf-subr.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/ctf-types.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/ctf-util.Po@am__quote@
@@ -687,7 +692,7 @@ clean-am: clean-generic clean-noinstLIBRARIES mostlyclean-am
 
 distclean: distclean-am
 	-rm -f $(am__CONFIG_DISTCLEAN_FILES)
-	-rm -rf $(DEPDIR) ./$(DEPDIR)
+	-rm -rf ./$(DEPDIR)
 	-rm -f Makefile
 distclean-am: clean-am distclean-compile distclean-generic \
 	distclean-hdr distclean-tags
@@ -735,7 +740,7 @@ installcheck-am:
 maintainer-clean: maintainer-clean-am
 	-rm -f $(am__CONFIG_DISTCLEAN_FILES)
 	-rm -rf $(top_srcdir)/autom4te.cache
-	-rm -rf $(DEPDIR) ./$(DEPDIR)
+	-rm -rf ./$(DEPDIR)
 	-rm -f Makefile
 maintainer-clean-am: distclean-am maintainer-clean-generic
 
diff --git a/libctf/config.h.in b/libctf/config.h.in
index 0ecb5bb7211..d81c500c5c3 100644
--- a/libctf/config.h.in
+++ b/libctf/config.h.in
@@ -9,10 +9,6 @@
 /* Define to 1 if you have the <byteswap.h> header file. */
 #undef HAVE_BYTESWAP_H
 
-/* Define to 1 if you have the declaration of `qsort_r', and to 0 if you
-   don't. */
-#undef HAVE_DECL_QSORT_R
-
 /* Define to 1 if you have the <endian.h> header file. */
 #undef HAVE_ENDIAN_H
 
@@ -31,6 +27,15 @@
 /* Define to 1 if you have the `pread' function. */
 #undef HAVE_PREAD
 
+/* Define to 1 if you have the `qsort_r' function. */
+#undef HAVE_QSORT_R
+
+/* Whether a qsort_r exists with a void *arg as its last arg. */
+#undef HAVE_QSORT_R_ARG_LAST
+
+/* Whether a qsort_r exists with the compar function as its last arg. */
+#undef HAVE_QSORT_R_COMPAR_LAST
+
 /* Define to 1 if you have the <stdint.h> header file. */
 #undef HAVE_STDINT_H
 
diff --git a/libctf/configure b/libctf/configure
index 4fb44eb2cc6..d485b1a7cec 100755
--- a/libctf/configure
+++ b/libctf/configure
@@ -620,10 +620,13 @@ ac_includes_default="\
 #endif"
 
 ac_header_list=
+ac_func_list=
 ac_subst_vars='am__EXEEXT_FALSE
 am__EXEEXT_TRUE
 LTLIBOBJS
 LIBOBJS
+NEED_CTF_QSORT_R_FALSE
+NEED_CTF_QSORT_R_TRUE
 zlibinc
 zlibdir
 ac_libctf_warn_cflags
@@ -1809,52 +1812,6 @@ $as_echo "$ac_res" >&6; }
   eval $as_lineno_stack; ${as_lineno_stack:+:} unset as_lineno
 
 } # ac_fn_c_check_func
-
-# ac_fn_c_check_decl LINENO SYMBOL VAR INCLUDES
-# ---------------------------------------------
-# Tests whether SYMBOL is declared in INCLUDES, setting cache variable VAR
-# accordingly.
-ac_fn_c_check_decl ()
-{
-  as_lineno=${as_lineno-"$1"} as_lineno_stack=as_lineno_stack=$as_lineno_stack
-  as_decl_name=`echo $2|sed 's/ *(.*//'`
-  as_decl_use=`echo $2|sed -e 's/(/((/' -e 's/)/) 0&/' -e 's/,/) 0& (/g'`
-  { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $as_decl_name is declared" >&5
-$as_echo_n "checking whether $as_decl_name is declared... " >&6; }
-if eval \${$3+:} false; then :
-  $as_echo_n "(cached) " >&6
-else
-  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
-/* end confdefs.h.  */
-$4
-int
-main ()
-{
-#ifndef $as_decl_name
-#ifdef __cplusplus
-  (void) $as_decl_use;
-#else
-  (void) $as_decl_name;
-#endif
-#endif
-
-  ;
-  return 0;
-}
-_ACEOF
-if ac_fn_c_try_compile "$LINENO"; then :
-  eval "$3=yes"
-else
-  eval "$3=no"
-fi
-rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
-fi
-eval ac_res=\$$3
-	       { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_res" >&5
-$as_echo "$ac_res" >&6; }
-  eval $as_lineno_stack; ${as_lineno_stack:+:} unset as_lineno
-
-} # ac_fn_c_check_decl
 cat >config.log <<_ACEOF
 This file contains any messages produced by compilers while
 running configure, to aid debugging if configure makes a mistake.
@@ -2142,6 +2099,7 @@ fi
 as_fn_append ac_header_list " stdlib.h"
 as_fn_append ac_header_list " unistd.h"
 as_fn_append ac_header_list " sys/param.h"
+as_fn_append ac_func_list " qsort_r"
 # Check that the precious variables saved in the cache have kept the same
 # value.
 ac_cache_corrupted=false
@@ -6401,23 +6359,108 @@ _ACEOF
 fi
 done
 
-ac_fn_c_check_decl "$LINENO" "qsort_r" "ac_cv_have_decl_qsort_r" "$ac_includes_default"
-if test "x$ac_cv_have_decl_qsort_r" = xyes; then :
-  ac_have_decl=1
-else
-  ac_have_decl=0
+
+
+
+
+  for ac_func in $ac_func_list
+do :
+  as_ac_var=`$as_echo "ac_cv_func_$ac_func" | $as_tr_sh`
+ac_fn_c_check_func "$LINENO" "$ac_func" "$as_ac_var"
+if eval test \"x\$"$as_ac_var"\" = x"yes"; then :
+  cat >>confdefs.h <<_ACEOF
+#define `$as_echo "HAVE_$ac_func" | $as_tr_cpp` 1
+_ACEOF
+
 fi
+done
 
-cat >>confdefs.h <<_ACEOF
-#define HAVE_DECL_QSORT_R $ac_have_decl
+
+
+
+if test $ac_cv_func_qsort_r = yes; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for qsort_r signature" >&5
+$as_echo_n "checking for qsort_r signature... " >&6; }
+if ${ac_cv_libctf_qsort_r_signature+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#undef qsort_r
+                          #include <stdlib.h>
+                          void qsort_r (void *, size_t, size_t,
+                                        int (*) (void const *, void const *,
+                                                 void *),
+                                        void *);
+                          void (*p) (void *, size_t, size_t,
+                                     int (*) (void const *, void const *,
+                                              void *),
+                                     void *) = qsort_r;
+
+int
+main ()
+{
+
+  ;
+  return 0;
+}
 _ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+  ac_cv_libctf_qsort_r_signature=GNU
+else
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#undef qsort_r
+	                     #include <stdlib.h>
+                             void qsort_r (void *, size_t, size_t, void *,
+                                           int (*) (void *,
+                                                    void const *,
+                                                    void const *));
+                             void (*p) (void *, size_t, size_t, void *,
+                                        int (*) (void *, void const *,
+                                                 void const *)) = qsort_r;
 
-case " $LIBOBJS " in
-  *" qsort_r.$ac_objext "* ) ;;
-  *) LIBOBJS="$LIBOBJS qsort_r.$ac_objext"
- ;;
+int
+main ()
+{
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+  ac_cv_libctf_qsort_r_signature=BSD
+else
+  ac_cv_libctf_qsort_r_signature=unknown
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_libctf_qsort_r_signature" >&5
+$as_echo "$ac_cv_libctf_qsort_r_signature" >&6; }
+fi
+
+case x$ac_cv_libctf_qsort_r_signature in
+  xGNU)
+$as_echo "#define HAVE_QSORT_R_ARG_LAST 1" >>confdefs.h
+;;
+  xBSD)
+$as_echo "#define HAVE_QSORT_R_COMPAR_LAST 1" >>confdefs.h
+;;
+  *) ac_cv_libctf_qsort_r_signature=unknown;;
 esac
 
+ if test "${ac_cv_libctf_qsort_r_signature}" = unknown; then
+  NEED_CTF_QSORT_R_TRUE=
+  NEED_CTF_QSORT_R_FALSE='#'
+else
+  NEED_CTF_QSORT_R_TRUE='#'
+  NEED_CTF_QSORT_R_FALSE=
+fi
+
 
 ac_config_files="$ac_config_files Makefile"
 
@@ -6561,6 +6604,10 @@ if test -z "${MAINTAINER_MODE_TRUE}" && test -z "${MAINTAINER_MODE_FALSE}"; then
 Usually this means the macro was only invoked conditionally." "$LINENO" 5
 fi
 
+if test -z "${NEED_CTF_QSORT_R_TRUE}" && test -z "${NEED_CTF_QSORT_R_FALSE}"; then
+  as_fn_error $? "conditional \"NEED_CTF_QSORT_R\" was never defined.
+Usually this means the macro was only invoked conditionally." "$LINENO" 5
+fi
 
 : "${CONFIG_STATUS=./config.status}"
 ac_write_fail=0
diff --git a/libctf/configure.ac b/libctf/configure.ac
index 8fd5388d2a0..beb90ba75cc 100644
--- a/libctf/configure.ac
+++ b/libctf/configure.ac
@@ -90,8 +90,48 @@ fi
 AC_C_BIGENDIAN
 AC_CHECK_HEADERS(byteswap.h endian.h)
 AC_CHECK_FUNCS(pread)
-AC_CHECK_DECLS([qsort_r])
-AC_LIBOBJ([qsort_r])
+
+dnl Check for qsort_r.  (Taken from gnulib.)
+AC_CHECK_FUNCS_ONCE([qsort_r])
+if test $ac_cv_func_qsort_r = yes; then
+  AC_CACHE_CHECK([for qsort_r signature], [ac_cv_libctf_qsort_r_signature],
+    [AC_LINK_IFELSE(
+       [AC_LANG_PROGRAM([[#undef qsort_r
+                          #include <stdlib.h>
+                          void qsort_r (void *, size_t, size_t,
+                                        int (*) (void const *, void const *,
+                                                 void *),
+                                        void *);
+                          void (*p) (void *, size_t, size_t,
+                                     int (*) (void const *, void const *,
+                                              void *),
+                                     void *) = qsort_r;
+                        ]])],
+       [ac_cv_libctf_qsort_r_signature=GNU],
+       [AC_LINK_IFELSE(
+          [AC_LANG_PROGRAM([[#undef qsort_r
+	                     #include <stdlib.h>
+                             void qsort_r (void *, size_t, size_t, void *,
+                                           int (*) (void *,
+                                                    void const *,
+                                                    void const *));
+                             void (*p) (void *, size_t, size_t, void *,
+                                        int (*) (void *, void const *,
+                                                 void const *)) = qsort_r;
+                           ]])],
+          [ac_cv_libctf_qsort_r_signature=BSD],
+          [ac_cv_libctf_qsort_r_signature=unknown])])])
+fi
+
+case x$ac_cv_libctf_qsort_r_signature in
+  xGNU)     AC_DEFINE([HAVE_QSORT_R_ARG_LAST], 1,
+	     [Whether a qsort_r exists with a void *arg as its last arg.]);;
+  xBSD)     AC_DEFINE([HAVE_QSORT_R_COMPAR_LAST], 1,
+	     [Whether a qsort_r exists with the compar function as its last arg.]);;
+  *) ac_cv_libctf_qsort_r_signature=unknown;;
+esac
+
+AM_CONDITIONAL(NEED_CTF_QSORT_R, test "${ac_cv_libctf_qsort_r_signature}" = unknown)
 
 AC_CONFIG_FILES(Makefile)
 AC_CONFIG_HEADERS(config.h)
diff --git a/libctf/ctf-archive.c b/libctf/ctf-archive.c
index a238edb66ba..90cd020b781 100644
--- a/libctf/ctf-archive.c
+++ b/libctf/ctf-archive.c
@@ -169,10 +169,11 @@ ctf_arc_write (const char *file, ctf_file_t ** ctf_files, size_t ctf_file_cnt,
       modent++;
     }
 
-  qsort_r ((ctf_archive_modent_t *) ((char *) archdr
-				     + sizeof (struct ctf_archive)),
-	   le64toh (archdr->ctfa_nfiles),
-	   sizeof (struct ctf_archive_modent), sort_modent_by_name, nametbl);
+  ctf_qsort_r ((ctf_archive_modent_t *) ((char *) archdr
+					 + sizeof (struct ctf_archive)),
+	       le64toh (archdr->ctfa_nfiles),
+	       sizeof (struct ctf_archive_modent), sort_modent_by_name,
+	       nametbl);
 
    /* Now the name table.  */
 
diff --git a/libctf/ctf-create.c b/libctf/ctf-create.c
index 227f62d8fd7..3beed887122 100644
--- a/libctf/ctf-create.c
+++ b/libctf/ctf-create.c
@@ -344,7 +344,7 @@ ctf_update (ctf_file_t *fp)
     }
   assert (i == nvars);
 
-  qsort_r (dvarents, nvars, sizeof (ctf_varent_t), ctf_sort_var, s0);
+  ctf_qsort_r (dvarents, nvars, sizeof (ctf_varent_t), ctf_sort_var, s0);
   t += sizeof (ctf_varent_t) * nvars;
 
   assert (t == (unsigned char *) buf + sizeof (ctf_header_t) + hdr.cth_typeoff);
diff --git a/libctf/ctf-decls.h b/libctf/ctf-decls.h
index 5e9ede48099..d12409e4b60 100644
--- a/libctf/ctf-decls.h
+++ b/libctf/ctf-decls.h
@@ -22,12 +22,45 @@
 
 #include "config.h"
 
-#if !HAVE_DECL_QSORT_R
 #include <stddef.h>
-void qsort_r (void *base, size_t nmemb, size_t size,
+#include <stdlib.h>
+
+#if HAVE_QSORT_R_ARG_LAST
+static inline void
+ctf_qsort_r (void *base, size_t nmemb, size_t size,
+	     int (*compar)(const void *, const void *, void *),
+	     void *arg)
+{
+  qsort_r (base, nmemb, size, compar, arg);
+}
+#elif HAVE_QSORT_R_COMPAR_LAST
+struct ctf_qsort_arg
+{
+  int (*compar) (const void *, const void *, void *);
+  void *arg;
+};
+
+static int
+ctf_qsort_compar_thunk (void *arg, const void *a, const void *b)
+{
+  struct ctf_qsort_arg *qsort_arg = (struct ctf_qsort_arg *) arg;
+
+  return qsort_arg->compar (a, b, arg);
+}
+
+static inline void
+ctf_qsort_r (void *base, size_t nmemb, size_t size,
+	     int (*compar)(const void *, const void *, void *),
+	     void *arg)
+{
+  struct ctf_qsort_arg thunk = { compar, arg };
+  qsort_r (base, nmemb, size, &thunk, ctf_qsort_compar_thunk);
+}
+#else
+void ctf_qsort_r (void *base, size_t nmemb, size_t size,
 	      int (*compar)(const void *, const void *, void *),
 	      void *arg);
-#endif /* !HAVE_DECL_QSORT_R */
+#endif
 
 #undef MAX
 #undef MIN
diff --git a/libctf/qsort_r.c b/libctf/ctf-qsort_r.c
index 6c334fdaf39..6cb221d6f54 100644
--- a/libctf/qsort_r.c
+++ b/libctf/ctf-qsort_r.c
@@ -30,7 +30,7 @@
 #include "ctf-decls.h"
 
 #ifndef _LIBC
-# define _quicksort qsort_r
+# define _quicksort ctf_qsort_r
 # define __compar_d_fn_t compar_d_fn_t
 typedef int (*compar_d_fn_t) (const void *, const void *, void *);
 #endif