fix build with MSVC and GCC

MSVC errors:
Quake\ls_main.c(321,11): error C2057: expected constant expression
Quake\ls_main.c(321,21): error C2466: cannot allocate an array of constant size 0

GCC error:
Quake/ls_main.c:321:9: error: variable-sized object may not be initialized

Quake/ls_main.c

@@ -317,7 +317,7 @@ static void LS_InitStandardLibraries(lua_State* state)
 
 static int LS_Print(lua_State* state)
 {
-	static const int MAX_LENGTH = 4096;  // MAXPRINTMSG
+	enum PrintDummyEnum { MAX_LENGTH = 4096 };  // See MAXPRINTMSG
 	char buf[MAX_LENGTH] = { '\0' };
 
 	char* bufptr = buf;