patch 8.2.1424: Mac build fails

Problem:    Mac build fails.
Solution:   Adjust configure to not fall back to Athena.  Adjust some other
            files.
diff --git a/src/os_macosx.m b/src/os_macosx.m
index 4c04395..0ac59b4 100644
--- a/src/os_macosx.m
+++ b/src/os_macosx.m
@@ -33,7 +33,7 @@
  * gui_mac.c are used then.  TODO: remove those instead?
  * But for MacVim we do need these ones.
  */
-#if defined(FEAT_CLIPBOARD) && (!defined(FEAT_GUI_ENABLED) || defined(FEAT_GUI_MACVIM))
+#if defined(FEAT_CLIPBOARD) && (!defined(FEAT_GUI_ENABLED))
 
 /* Used to identify clipboard data copied from Vim. */