patch 9.0.1168: code to enable/disable mouse is not from terminfo/termcap

Problem:    Code to enable/disable mouse is not from terminfo/termcap.
Solution:   Request the "XM" entry and use it to set 'ttymouse' if possible.
diff --git a/src/version.c b/src/version.c
index a218a71..56cbdd4 100644
--- a/src/version.c
+++ b/src/version.c
@@ -696,6 +696,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1168,
+/**/
     1167,
 /**/
     1166,