define STRING and XSTRING in q_shared.h (#4054)

code/sys/sys_main.c

@@ -517,8 +517,6 @@ int main( int argc, char **argv )
 	// Run time
 	const SDL_version *ver = SDL_Linked_Version( );
 
-#define STRING(s) #s
-#define XSTRING(s) STRING(s)
 #define MINSDL_VERSION \
 	XSTRING(MINSDL_MAJOR) "." \
 	XSTRING(MINSDL_MINOR) "." \