updated for version 7.3.512
Problem:    undofile() returns a useless name when passed an empty string.
Solution:   Return an empty string. (Christian Brabandt)
diff --git a/src/version.c b/src/version.c
index b2f9a98..ce22d9f 100644
--- a/src/version.c
+++ b/src/version.c
@@ -715,6 +715,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    512,
+/**/
     511,
 /**/
     510,