Windows cl.exe does not support -Wextra other flags

CMakeLists.txt

@@ -169,7 +169,12 @@ 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)
+# Windows cl.exe does not support the -Wextra, -Wno-unused and -Werror flags.
+set(CMAKE_C_FLAGS "-Wall ${CMAKE_C_FLAGS}")
+else()
 set(CMAKE_C_FLAGS "-Wall -Wextra -Wno-unused -Werror ${CMAKE_C_FLAGS}")
+endif()
 
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 # Build Options