patch 9.0.0231: expanding "**" may loop forever with directory links

Problem:    Expanding "**" may loop forever with directory links.
Solution:   Check for being interrupted. (closes #10946)
diff --git a/src/version.c b/src/version.c
index 9ce33cd..9b98edc 100644
--- a/src/version.c
+++ b/src/version.c
@@ -732,6 +732,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    231,
+/**/
     230,
 /**/
     229,