patch 8.1.0633: crash when out of memory while opening a terminal window

Problem:    Crash when out of memory while opening a terminal window.
Solution:   Handle out-of-memory more gracefully.
diff --git a/src/version.c b/src/version.c
index 2452ae0..6956225 100644
--- a/src/version.c
+++ b/src/version.c
@@ -800,6 +800,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    633,
+/**/
     632,
 /**/
     631,