force use system CRT to build static SDL2

Author: MoeMod

3rdparty/CMakeLists.txt

@@ -26,6 +26,7 @@ if(XASH_SDL)
 				add_definitions(-D_ftol2_sse=SDL_ftol2_sse) # fix x86 compile
 			endif()
 			set(DIRECTX OFF CACHE BOOL "" FORCE) # win10 arm dont have dx8
+			set(LIBC ON CACHE BOOL "" FORCE) # win10 arm dont have dx8
 			add_subdirectory(SDL2 EXCLUDE_FROM_ALL)
 			target_link_libraries(sdl2 INTERFACE SDL2-static)
 		endif()