diff --git a/dumb/CMakeLists.txt b/dumb/CMakeLists.txt
index 63ce020e1..85e052209 100644
--- a/dumb/CMakeLists.txt
+++ b/dumb/CMakeLists.txt
@@ -9,7 +9,7 @@ set( CMAKE_C_FLAGS_DEBUG "${CMAKE_C_FLAGS_DEBUG} -D_DEBUG -DDEBUGMODE=1" )
 
 if( ZD_CMAKE_COMPILER_IS_GNUC_COMPATIBLE )
 	set( CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wall -Wno-pointer-sign -Wno-uninitialized" )
-	if( NOT CMAKE_C_COMPILER_ID STREQUAL "GNU" OR CMAKE_C_COMPILER_VERSION VERSION_GREATER "4.5" )
+	if( CMAKE_C_COMPILER_ID STREQUAL "GNU" AND CMAKE_C_COMPILER_VERSION VERSION_GREATER "4.5" )
 		set( CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wno-unused-but-set-variable" )
 	endif()
 endif()
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index b39221759..94ac6fb32 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -461,7 +461,7 @@ if( ZD_CMAKE_COMPILER_IS_GNUCXX_COMPATIBLE )
 	set( CMAKE_CXX_FLAGS_MINSIZEREL "${REL_CXX_FLAGS} ${CMAKE_CXX_FLAGS_MINSIZEREL}" )
 	set( CMAKE_CXX_FLAGS_RELWITHDEBINFO "${REL_CXX_FLAGS} ${CMAKE_CXX_FLAGS_RELWITHDEBINFO}" )
 
-	if(NOT CMAKE_CXX_COMPILER_ID STREQUAL "GNU" OR CMAKE_CXX_COMPILER_VERSION VERSION_GREATER "4.5")
+	if(CMAKE_CXX_COMPILER_ID STREQUAL "GNU" AND CMAKE_CXX_COMPILER_VERSION VERSION_GREATER "4.5")
 		set( CMAKE_C_FLAGS "-Wno-unused-result ${CMAKE_C_FLAGS}" )
 		set( CMAKE_CXX_FLAGS "-Wno-unused-result ${CMAKE_CXX_FLAGS}" )
 	endif()