From d5914ecbb0285aea1eb2b9432d6e91155877fd95 Mon Sep 17 00:00:00 2001
From: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Date: Thu, 9 Jun 2016 21:53:59 +0200
Subject: [PATCH] configure: only add -Wunused-result if supported by the
 compiler

Old gcc versions such as 4.3.x do not support -Wunused-result, so
instead of unconditionally using this warning, only use it if supported
by the compiler.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
---
Submitted upstream: https://github.com/obgm/libcoap/pull/32

 configure.ac | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/configure.ac b/configure.ac
index f4452ac..6354fcf 100644
--- a/configure.ac
+++ b/configure.ac
@@ -110,12 +110,12 @@ WARNING_CFLAGS="\
 -Wswitch-default \
 -Wswitch-enum \
 -Wunused \
--Wunused-result \
 "
 
 # check whether or not the compiler supports -Wlogical-op (clang does not...)
 AX_CHECK_COMPILE_FLAG([-Wlogical-op], [WARNING_CFLAGS="$WARNING_CFLAGS -Wlogical-op"],,[-Werror])
 AX_CHECK_COMPILE_FLAG([-fdiagnostics-color], [CFLAGS="$CFLAGS -fdiagnostics-color"],,[-Werror])
+AX_CHECK_COMPILE_FLAG([-Wunused-result], [WARNING_CFLAGS="$WARNING_CFLAGS -Wunused-result"])
 
 AC_SUBST([WARNING_CFLAGS])
 
-- 
2.7.4