patch 7.4.763

Problem:    Building with Lua 5.1 doesn't work.
Solution:   Define lua_replace and lua_remove. (KF Leong)

src/version.c

@@ -741,6 +741,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    763,
 /**/
     762,
 /**/