From dd320959701b1ecba6575b653afa4e914ac2f48f Mon Sep 17 00:00:00 2001
From: Andrea Mazzoleni <amadvance@gmail.com>
Date: Sun, 6 Nov 2016 16:47:26 +0100
Subject: [PATCH] Avoid clang to report unused options as warning

Otherwise this conflicts with the -Werror flag
---
 configure.ac | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/configure.ac b/configure.ac
index bfcd74d9..845b6488 100644
--- a/configure.ac
+++ b/configure.ac
@@ -337,7 +337,12 @@ AC_ARG_ENABLE([debug],
 
 AC_ARG_ENABLE([warning-as-error],
 	[AS_HELP_STRING([--enable-warning-as-error],[stop build on warnings])],
-	CFLAGS="$CFLAGS -Werror",
+	[
+	AC_CHECK_CC_OPT([-Werror], CFLAGS="$CFLAGS -Werror", [])
+	dnl This avoid the Darwin error: clang: error: argument unused during compilation: '-pthread'
+	dnl See: https://llvm.org/bugs/show_bug.cgi?id=7798
+	AC_CHECK_CC_OPT([-Wno-error=unused-command-line-argument], CFLAGS="$CFLAGS -Wno-error=unused-command-line-argument", [])
+	],
 	[])
 
 AC_ARG_ENABLE([warning],