CPack: Deprecate OSXX11 generator

The CPack OSXX11 generator has not had any updates since 2011 except as
part of sweeping maintenance changes.  It also creates packages with a
OSXScriptLauncher binary that has only ppc and i386 architectures which
are not supported by Apple anymore.  Furthermore, the generator is not
even mentioned in our documentation.  Add a deprecation warning.

Fixes: #20235

Help/release/dev/cpack-deprecate-old-macos-generators.rst

@@ -3,3 +3,4 @@ cpack-deprecate-old-macos-generators
 
 * The :cpack_gen:`CPack PackageMaker Generator` generator has been
   deprecated because Xcode no longer distributes the PackageMaker tools.
+  The undocumented ``OSXX11`` generator has also been deprecated.

Modules/CPack.cmake

@@ -563,7 +563,7 @@ if(NOT CPACK_GENERATOR)
       if(APPLE)
         option(CPACK_BINARY_BUNDLE       "Enable to build OSX bundles"      OFF)
         option(CPACK_BINARY_DRAGNDROP    "Enable to build OSX Drag And Drop package" OFF)
-        option(CPACK_BINARY_OSXX11       "Enable to build OSX X11 packages"      OFF)
+        option(CPACK_BINARY_OSXX11       "Enable to build OSX X11 packages (deprecated)" OFF)
         option(CPACK_BINARY_PACKAGEMAKER "Enable to build PackageMaker packages (deprecated)" OFF)
         option(CPACK_BINARY_PRODUCTBUILD "Enable to build productbuild packages" OFF)
         mark_as_advanced(

Source/CPack/cmCPackOSXX11Generator.cxx

@@ -178,6 +178,9 @@ int cmCPackOSXX11Generator::PackageFiles()
 
 int cmCPackOSXX11Generator::InitializeInternal()
 {
+  cmCPackLogger(cmCPackLog::LOG_WARNING,
+                "The OSXX11 generator is deprecated "
+                "and will be removed in a future version.\n");
   cmCPackLogger(cmCPackLog::LOG_DEBUG,
                 "cmCPackOSXX11Generator::Initialize()" << std::endl);
   std::vector<std::string> path;