updated for version 7.4.638

Problem:    Can't build with Lua 5.3 on Windows.
Solution:   use luaL_optinteger() instead of LuaL_optlong(). (Ken Takata)

src/version.c

@@ -741,6 +741,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    638,
 /**/
     637,
 /**/