diff --git a/CMakeLists.txt b/CMakeLists.txt
index 800d76cbf..9a324692f 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -169,7 +169,9 @@ find_package(Threads)
 # Example for map file and custom linker script
 #set(CMAKE_EXE_LINKER_FLAGS " -Xlinker -Map=output.map -T\"${CMAKE_CURRENT_SOURCE_DIR}/linker.ld\"")
 
-if(WIN32)
+if(DEFINED WARNING_C_FLAGS)
+set(CMAKE_C_FLAGS "${WARNING_C_FLAGS} ${CMAKE_C_FLAGS}")
+elseif(WIN32)
 # Windows cl.exe does not support the -Wextra, -Wno-unused and -Werror flags.
 set(CMAKE_C_FLAGS "-Wall ${CMAKE_C_FLAGS}")
 else()