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_member_constants.m4 b/m4/ax_cxx_member_constants.m4
index a1a012a..ad5597b 100644
--- a/m4/ax_cxx_member_constants.m4
+++ b/m4/ax_cxx_member_constants.m4
@@ -20,18 +20,17 @@
 #   and this notice are preserved. This file is offered as-is, without any
 #   warranty.
 
-#serial 7
+#serial 8
 
 AU_ALIAS([AC_CXX_MEMBER_CONSTANTS], [AX_CXX_MEMBER_CONSTANTS])
 AC_DEFUN([AX_CXX_MEMBER_CONSTANTS],
 [AC_CACHE_CHECK(whether the compiler supports member constants,
 ax_cv_cxx_member_constants,
-[AC_LANG_SAVE
- AC_LANG_CPLUSPLUS
- AC_TRY_COMPILE([class C {public: static const int i = 0;}; const int C::i;],
-[return C::i;],
- ax_cv_cxx_member_constants=yes, ax_cv_cxx_member_constants=no)
- AC_LANG_RESTORE
+[AC_LANG_PUSH([C++])
+ AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[class C {public: static const int i = 0;}; const int C::i;]],
+ [[return C::i;]])],
+ [ax_cv_cxx_member_constants=yes], [ax_cv_cxx_member_constants=no])
+ AC_LANG_POP([C++])
 ])
 if test "$ax_cv_cxx_member_constants" = yes; then
   AC_DEFINE(HAVE_MEMBER_CONSTANTS,,[define if the compiler supports member constants])