updated for version 7.3.581

Problem:    Problems compiling with Python.
Solution:   Pick UCS2 or UCS4 function at runtime. (lilydjwg)

src/version.c

@@ -714,6 +714,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    581,
 /**/
     580,
 /**/