autoconf: Some gcc versions require AC_PROG_CC_STDC to provide std c.

In particular 4.1.2, to define __STDC_VERSION__

diff --git a/m4/usual.m4 b/m4/usual.m4
index 843392dd6e0e9ecc5d6546e8a208d4f7ea0bc485..5d61bcecf7d82c0b28c09349b3db4e6fe77aff9f 100644 (file)
--- a/m4/usual.m4
+++ b/m4/usual.m4
@@ -44,7 +44,7 @@ dnl
 dnl AC_USUAL_PROGRAM_CHECK:  Simple C environment: CC, CPP, INSTALL
 dnl
 AC_DEFUN([AC_USUAL_PROGRAM_CHECK], [
-AC_PROG_CC
+AC_PROG_CC_STDC
 AC_PROG_CPP
 dnl Check if compiler supports __func__
 AC_CACHE_CHECK([whether compiler supports __func__], pgac_cv_funcname_func,