patch 8.2.2442: automatic GUI selection does not check for GTK 3

Problem:    Automatic GUI selection does not check for GTK 3.
Solution:   Make SKIP_GTK3 empty for automatic GUI support.  Set SKIP_GTK3 to
            YES when checking for GTK2.
diff --git a/src/version.c b/src/version.c
index 5555c77..d802f9c 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2442,
+/**/
     2441,
 /**/
     2440,