diff --git a/CMakeLists.txt b/CMakeLists.txt
index 47ed206..2ab65ad 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -3,7 +3,7 @@ cmake_minimum_required (VERSION 2.8.5)
 
 # Moar warnings
 if ("${CMAKE_C_COMPILER_ID}" MATCHES "GNU" OR CMAKE_COMPILER_IS_GNUC)
-	set (CMAKE_C_FLAGS "-std=gnu99")
+	set (CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -std=gnu99")
 	set (CMAKE_C_FLAGS_DEBUG
 		"${CMAKE_C_FLAGS_DEBUG} -Wall -Wextra -Wno-missing-field-initializers")
 endif ("${CMAKE_C_COMPILER_ID}" MATCHES "GNU" OR CMAKE_COMPILER_IS_GNUC)