From fdc445ea8d33568f5f02899efe15ff960f8341ab Mon Sep 17 00:00:00 2001
From: "Yury V. Zaytsev" <yury@shurup.com>
Date: Sun, 3 Nov 2024 08:55:43 +0100
Subject: [PATCH] buildsys: fix enabling C standards for older autoconf broken
 in 1bc8abd7

Signed-off-by: Yury V. Zaytsev <yury@shurup.com>
---
 configure.ac | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/configure.ac b/configure.ac
index 059930bcc..2acd2b33e 100644
--- a/configure.ac
+++ b/configure.ac
@@ -42,6 +42,11 @@ AC_CHECK_TOOLS([AR], [ar gar])
 
 AC_PROG_CC
 
+# AC_PROG_CC doesn't try enabling C99 in autoconf 2.69 and below, but
+# AC_PROG_CC_C99 is deprecated in newer ones. In autoconf 2.70+ both
+# will try enabling features up to C11.
+m4_version_prereq([2.70], [AC_PROG_CC], [AC_PROG_CC_C99])
+
 mc_CHECK_CFLAGS
 
 CFLAGS_OPTS=""