Try to fix msvc build

build_msvc.bat

@@ -1,13 +1,16 @@
 @echo off
 rem launch this from msvc-enabled console
 
-set CXXFLAGS=/std:c++17 /O2 /FC /W4 /nologo
-set INCLUDES=/I SDL2\include /I thirdparty /I build
-set LIBS=SDL2\lib\x64\SDL2.lib SDL2\lib\x64\SDL2main.lib Shell32.lib
+set COMMON_CXXFLAGS=/std:c++17 /O2 /FC /W4 /nologo /I thirdparty /I build
+set SDL2_CXXFLAGS=%COMMON_CXXFLAGS% /I SDL2\include
+set RGFW_CXXFLAGS=%COMMON_CXXFLAGS%
+set COMMON_LIBS=Shell32.lib
+set SDL2_LIBS=%COMMON_LIBS% SDL2\lib\x64\SDL2.lib SDL2\lib\x64\SDL2main.lib -SUBSYSTEM:windows
+set RGFW_LIBS=%COMMON_LIBS% -SUBSYSTEM:windows /entry:mainCRTStartup
 
 mkdir build
-cl.exe %CXXFLAGS% /Febuild\png2c src\png2c.c /link Shell32.lib -SUBSYSTEM:console
+cl.exe %COMMON_CXXFLAGS% /Febuild\png2c src\png2c.c /link %COMMON_LIBS% -SUBSYSTEM:console
 build\png2c.exe assets\digits.png digits > build\digits.h
 build\png2c.exe assets\penger_walk_sheet.png penger > build\penger_walk_sheet.h
-cl.exe %CXXFLAGS% %INCLUDES% /Fesowon src/main.c /link %LIBS% -SUBSYSTEM:windows
-cl.exe %CXXFLAGS% /Fesowon_rgfw src/main_rgfw.c /link Shell32.lib -SUBSYSTEM:windows /entry:mainCRTStartup
+cl.exe %SDL2_CXXFLAGS% /Fesowon src/main.c /link %SDL2_LIBS%
+cl.exe %RGFW_CXXFLAGS% /Fesowon_rgfw src/main_rgfw.c /link %RGFW_LIBS%