patch 8.0.1665: when running a terminal from the GUI 'term' is not useful

Problem:    When running a terminal from the GUI 'term' is not useful.
Solution:   Use $TERM in the GUI if it starts with "xterm". (closes #2776)
diff --git a/src/version.c b/src/version.c
index a9b4dca..b29d64c 100644
--- a/src/version.c
+++ b/src/version.c
@@ -763,6 +763,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1665,
+/**/
     1664,
 /**/
     1663,