From b51a99ae358b3295de272bb3c3edb6913eeb0fd4 Mon Sep 17 00:00:00 2001
From: Nikita Popov <nikita.ppv@gmail.com>
Date: Sun, 16 Sep 2018 16:51:03 +0200
Subject: [PATCH] Enable C99 in autoconf

This is essentially a no-op, because any current compiler already
defaults to C99 or C11.

When using language features from C99 or C11, please don't forget
that header files also need to be compatible with C++.
---
 configure.ac | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/configure.ac b/configure.ac
index 052c39cf47c..119323d1692 100644
--- a/configure.ac
+++ b/configure.ac
@@ -183,8 +183,7 @@ AC_PROG_CC([cc gcc])
 PHP_DETECT_ICC
 PHP_DETECT_SUNCC
 AC_PROG_CC_C_O
-dnl Change to AC_PROG_CC_STDC when we start requiring a post-2.13 autoconf
-dnl AC_PROG_CC_STDC
+AC_PROG_CC_C99
 AC_PROG_CPP
 AC_USE_SYSTEM_EXTENSIONS
 AC_PROG_LN_S