Check for c99 with autoconf versions prior to 2.70

diff --git a/configure.ac b/configure.ac
index f6f5f21fc5433e5ad60e41889082d0841578738f..9aa781a126af8f355c6ed1c6d8a0b5335e92b980 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -280,7 +280,7 @@ ACX_CHECK_COMPILER_FLAG(g, [CFLAGS="$CFLAGS -g"])
 ACX_CHECK_COMPILER_FLAG(O2, [CFLAGS="$CFLAGS -O2"])
 default_cflags=yes
 fi
-AC_PROG_CC
+m4_version_prereq([2.70], [AC_PROG_CC], [AC_PROG_CC_STDC])
 ACX_DEPFLAG
 ACX_DETERMINE_EXT_FLAGS_UNBOUND