Enable Hardware Enforced Stack Protection in Windows

With this commit, both Mozc and Qt executables are build with the
following flag set:

  IMAGE_DLLCHARACTERISTICS_EX_CET_COMPAT [1]

This is an optional flag that tells the OS that executables are
compatible with Intel Control Flow Enforcement Technology (CET) [2].

The flag simply ignored on environment where the feature is not
available.  There must be no user observable behavior change.

Closes google#835.

 [1]: https://learn.microsoft.com/en-us/windows/win32/debug/pe-format#extended-dll-characteristics
 [2]: https://www.intel.com/content/www/us/en/developer/articles/technical/technical-look-control-flow-enforcement-technology.html

PiperOrigin-RevId: 576253756

src/build_tools/build_qt.py

@@ -345,6 +345,7 @@ def make_configure_options(args: argparse.Namespace) -> list[str]:
       ]
   elif is_windows():
     qt_configure_options += ['-force-debug-info',
+                             '-intelcet',
                              '-ltcg',  # Note: ignored in debug build
                              '-no-feature-texthtmlparser',
                              '-no-freetype',

src/gyp/common_win.gypi

@@ -375,6 +375,9 @@
           'user32.lib',
           'uuid.lib',
         ],
+        'AdditionalOptions': [
+          '/CETCOMPAT',
+        ],
         'DataExecutionPrevention': '2',        # /NXCOMPAT
         'EnableCOMDATFolding': '2',            # /OPT:ICF
         'GenerateDebugInformation': 'true',    # /DEBUG