patch 8.2.1422: the Mac GUI implementation is outdated

Problem:    The Mac GUI implementation is outdated and probably doesn't even
            work.
Solution:   Remove the Mac GUI code.  The MacVim project provides the
            supported Vim GUI version.
diff --git a/src/feature.h b/src/feature.h
index 4917527..0c68f79 100644
--- a/src/feature.h
+++ b/src/feature.h
@@ -632,7 +632,6 @@
 #if defined(FEAT_NORMAL) \
     && (defined(FEAT_GUI_GTK) \
 	|| (defined(FEAT_GUI_MOTIF) && defined(HAVE_XM_NOTEBOOK_H)) \
-	|| defined(FEAT_GUI_MAC) \
 	|| defined(FEAT_GUI_HAIKU) \
 	|| (defined(FEAT_GUI_MSWIN) \
 	    && (!defined(_MSC_VER) || _MSC_VER > 1020)))
@@ -646,8 +645,7 @@
 #if defined(FEAT_NORMAL)
 # define FEAT_BROWSE_CMD
 # if defined(FEAT_GUI_MSWIN) || defined(FEAT_GUI_MOTIF) || defined(FEAT_GUI_ATHENA) \
-	|| defined(FEAT_GUI_GTK) || defined(FEAT_GUI_HAIKU) || defined(FEAT_GUI_PHOTON) \
-	|| defined(FEAT_GUI_MAC)
+	|| defined(FEAT_GUI_GTK) || defined(FEAT_GUI_HAIKU) || defined(FEAT_GUI_PHOTON)
 #  define FEAT_BROWSE
 # endif
 #endif
@@ -657,8 +655,7 @@
  * there is no terminal version, and on Windows we can't figure out how to
  * fork one off with :gui.
  */
-#if (defined(FEAT_GUI_MSWIN) && !defined(VIMDLL)) \
-	    || (defined(FEAT_GUI_MAC) && !defined(MACOS_X_DARWIN))
+#if defined(FEAT_GUI_MSWIN) && !defined(VIMDLL)
 # define ALWAYS_USE_GUI
 #endif
 
@@ -673,8 +670,7 @@
 	|| defined(FEAT_GUI_GTK) \
 	|| defined(FEAT_GUI_PHOTON) \
 	|| defined(FEAT_GUI_HAIKU) \
-	|| defined(FEAT_GUI_MSWIN) \
-	|| defined(FEAT_GUI_MAC)
+	|| defined(FEAT_GUI_MSWIN)
 #  define FEAT_CON_DIALOG
 #  define FEAT_GUI_DIALOG
 # else
@@ -690,7 +686,7 @@
 #if defined(FEAT_GUI_DIALOG) && \
 	(defined(FEAT_GUI_MOTIF) || defined(FEAT_GUI_ATHENA) \
 	 || defined(FEAT_GUI_GTK) || defined(FEAT_GUI_MSWIN) \
-	 || defined(FEAT_GUI_PHOTON) || defined(FEAT_GUI_MAC) \
+	 || defined(FEAT_GUI_PHOTON) \
 	 || defined(FEAT_GUI_HAIKU))
 # define FEAT_GUI_TEXTDIALOG
 # ifndef ALWAYS_USE_GUI
@@ -705,11 +701,6 @@
 # define FEAT_TERMGUICOLORS
 #endif
 
-// Mac specific thing: Codewarrior interface.
-#ifdef FEAT_GUI_MAC
-# define FEAT_CW_EDITOR
-#endif
-
 /*
  * +vartabs		'vartabstop' and 'varsofttabstop' options.
  */
@@ -1091,8 +1082,7 @@
 #endif
 
 #if defined(FEAT_MZSCHEME) && (defined(FEAT_GUI_MSWIN) || defined(FEAT_GUI_GTK)    \
-	|| defined(FEAT_GUI_MOTIF) || defined(FEAT_GUI_ATHENA)	\
-	|| defined(FEAT_GUI_MAC))
+	|| defined(FEAT_GUI_MOTIF) || defined(FEAT_GUI_ATHENA))
 # define MZSCHEME_GUI_THREADS
 #endif