updated for version 7.4.578

Problem:    Using getcurpos() after "$" in an empty line returns a negative
            number.
Solution:   Don't add one when this would overflow. (Hirohito Higashi)

src/version.c

@@ -741,6 +741,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    578,
 /**/
     577,
 /**/