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.

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    2442,
 /**/
     2441,
 /**/