From 318a730c459a8524d7030d261946c35815dd4b29 Mon Sep 17 00:00:00 2001
From: Dmitry Marakasov <amdmi3@amdmi3.ru>
Date: Mon, 1 Aug 2011 22:17:32 +0400
Subject: [PATCH] Check whether -Wno-unused-but-set-variable is supported
 before using it. It seems to only be available on recent (>=4.6) versions of
 gcc.

---
 src/CMakeLists.txt | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index ce53651b0..5bdfc7eee 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -209,6 +209,8 @@ endif(BUILD_SERVER)
 # Set some optimizations and tweaks
 #
 
+include(CheckCCompilerFlag)
+
 if(MSVC)
 	# Visual Studio
 
@@ -236,7 +238,10 @@ else()
 	endif()
 	
 	if(NOT APPLE)
-		set(WARNING_FLAGS "${WARNING_FLAGS} -Wno-unused-but-set-variable")
+		check_c_compiler_flag("-Wno-unused-but-set-variable" HAS_UNUSED_BUT_SET_VARIABLE_WARNING)
+		if(HAS_UNUSED_BUT_SET_VARIABLE_WARNING)
+			set(WARNING_FLAGS "${WARNING_FLAGS} -Wno-unused-but-set-variable")
+		endif(HAS_UNUSED_BUT_SET_VARIABLE_WARNING)
 	endif()
 	
 	if(APPLE)