Increase warning level for MSVC

CMakeLists.txt

@@ -36,6 +36,15 @@ if(CMAKE_COMPILER_IS_GNUCC OR CMAKE_COMPILER_IS_GNUCXX OR CMAKE_COMPILER_IS_CLAN
 	if(USE_LIBC++)
 		set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -stdlib=libc++")
 	endif()
+elseif(MSVC)
+	if(CMAKE_CXX_FLAGS MATCHES "/W[0-4]")
+		string(REGEX REPLACE "/W[0-4]" "/W4" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
+	else()
+		set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /W4")
+	endif()
+
+	# Disable pointless constant condition warnings
+	set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /wd4127 /wd4201")
 endif()
 
 if(WIN32)