patch 9.1.0064: No Wayland support

Problem:  No Wayland support
Solution: Add Wayland UI support
          (lilydjwg)

closes: #9639

Signed-off-by: lilydjwg <lilydjwg@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/testdir/check.vim b/src/testdir/check.vim
index 82abb64..e67d39a 100644
--- a/src/testdir/check.vim
+++ b/src/testdir/check.vim
@@ -160,6 +160,14 @@
   endif
 endfunc
 
+" Command to Check for pure X11 (no Wayland)
+command -nargs=0 CheckX11 call CheckX11()
+func CheckX11()
+  if !empty($WAYLAND_DISPLAY) || empty($DISPLAY)
+    throw 'Skipped: not pure X11 environment'
+  endif
+endfunc
+
 " Command to check that we are using the GUI
 command CheckGui call CheckGui()
 func CheckGui()