patch 9.0.0923: second SIGWINCH signal may be ignored

Problem:    Second SIGWINCH signal may be ignored.
Solution:   When set_shellsize() is busy when called then run the inner code
            again when it's done.  (issue #424)
diff --git a/src/version.c b/src/version.c
index c73f1c4..cd2023c 100644
--- a/src/version.c
+++ b/src/version.c
@@ -696,6 +696,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    923,
+/**/
     922,
 /**/
     921,