Replace AC_TRY_COMPILE and AC_LANG_

Autoconf 2.50 in 2001 made several macros obsolete. These include macros
for temporary changing the language - AC_LANG_SAVE, AC_LANG_CPLUSPLUS,
AC_LANG_C, and AC_LANG_RESTORE. Instead of these the AC_LANG_PUSH and
AC_LANG_POP macros should be used with later Autoconf versions.

AC_TRY_COMPILE macros should be replaced with AC_COMPILE_IFELSE.

Refs:
- http://git.savannah.gnu.org/cgit/autoconf.git/tree/NEWS
- https://www.gnu.org/software/autoconf/manual/autoconf-2.69/html_node/Language-Choice.html
- https://www.gnu.org/software/autoconf/manual/autoconf-2.69/html_node/Obsolete-Macros.html

1 files changed, 6 insertions, 7 deletions

diff --git a/m4/ax_cxx_new_for_scoping.m4 b/m4/ax_cxx_new_for_scoping.m4
index 2b23f32..4676b0d 100644
--- a/m4/ax_cxx_new_for_scoping.m4
+++ b/m4/ax_cxx_new_for_scoping.m4
@@ -22,23 +22,22 @@
 #   and this notice are preserved. This file is offered as-is, without any
 #   warranty.
 
-#serial 7
+#serial 8
 
 AU_ALIAS([AC_CXX_NEW_FOR_SCOPING], [AX_CXX_NEW_FOR_SCOPING])
 AC_DEFUN([AX_CXX_NEW_FOR_SCOPING],
 [AC_CACHE_CHECK(whether the compiler accepts the new for scoping rules,
 ax_cv_cxx_new_for_scoping,
-[AC_LANG_SAVE
- AC_LANG_CPLUSPLUS
- AC_TRY_COMPILE(,[
+[AC_LANG_PUSH([C++])
+ AC_COMPILE_IFELSE([AC_LANG_PROGRAM([], [[
   int z = 0;
   for (int i = 0; i < 10; ++i)
     z = z + i;
   for (int i = 0; i < 10; ++i)
     z = z - i;
-  return z;],
- ax_cv_cxx_new_for_scoping=yes, ax_cv_cxx_new_for_scoping=no)
- AC_LANG_RESTORE
+  return z;]])],
+ [ax_cv_cxx_new_for_scoping=yes], [ax_cv_cxx_new_for_scoping=no])
+ AC_LANG_POP([C++])
 ])
 if test "$ax_cv_cxx_new_for_scoping" = yes; then
   AC_DEFINE(HAVE_NEW_FOR_SCOPING,,[define if the compiler accepts the new for scoping rules])