fix MinGW compilation (#195)

Author: hch12907

src/CMakeLists.txt

@@ -269,6 +269,10 @@ waifu2x_add_shader(waifu2x_postproc_tta.comp)
 
 add_custom_target(generate-spirv DEPENDS ${SHADER_SPV_HEX_FILES})
 
+if(MINGW)
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -municode")
+endif()
+
 add_executable(waifu2x-ncnn-vulkan main.cpp waifu2x.cpp)
 
 add_dependencies(waifu2x-ncnn-vulkan generate-spirv)