CXX Flags aren't definitions

CMakeLists.txt

@@ -321,15 +321,15 @@ endif()
 
 # Compiler settings
 if (CMAKE_COMPILER_IS_GNUCC)
-    add_definitions (-Wall -Wextra -Wno-unused-parameter -Wno-reorder -std=c++98 -pedantic -Wno-long-long)
+    SET(CMAKE_CXX_FLAGS "-Wall -Wextra -Wno-unused-parameter -Wno-reorder -std=c++98 -pedantic -Wno-long-long ${CMAKE_CXX_FLAGS}")
 
     # Silence warnings in OGRE headers. Remove once OGRE got fixed!
-    add_definitions (-Wno-ignored-qualifiers)
+    SET(CMAKE_CXX_FLAGS "-Wno-ignored-qualifiers ${CMAKE_CXX_FLAGS}")
 
     execute_process(COMMAND ${CMAKE_C_COMPILER} -dumpversion
                 OUTPUT_VARIABLE GCC_VERSION)
     if ("${GCC_VERSION}" VERSION_GREATER 4.6 OR "${GCC_VERSION}" VERSION_EQUAL 4.6)
-        add_definitions (-Wno-unused-but-set-parameter)
+        SET(CMAKE_CXX_FLAGS "-Wno-unused-but-set-parameter ${CMAKE_CXX_FLAGS}")
     endif("${GCC_VERSION}" VERSION_GREATER 4.6 OR "${GCC_VERSION}" VERSION_EQUAL 4.6)
 endif (CMAKE_COMPILER_IS_GNUCC)