updated for version 7.3.512

Problem:    undofile() returns a useless name when passed an empty string.
Solution:   Return an empty string. (Christian Brabandt)

src/version.c

@@ -714,6 +714,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    512,
 /**/
     511,
 /**/