[community triplet, ms-gdkx] xbox updates for October 2025 new layouts

[walbourn]

For the October 2025 Microsoft GDK, we are introducing a 'new layout' directory structure. Along with this is a new set of environment variables.

This PR updates the four xbox community triplets to handle both new and old layouts, and the ms-gdkx stub port as well.

Note that for October 2025, we offer both new and old layouts, but developers can optionally only install new layouts. We will eventually remove the old layouts entirely in a future GDK.

[walbourn]

Running a test now for a bunch of ports using October 2025 new layout only.

direcxtk12, directxtex, directxmesh, and uvatlas build with xbox triplets with their October 2025 updates. These ports have a direct dependency on ms-gdkx when building for xbox because they make use of the special DirectX 12.X variant.

directxtk12 will work once I complete my port updates for October 2025.

The directxtex[xbox]:x64-windows feature doesn't work yet because GameDKXboxLatest is not pass-through for x64-windows. It does work if you add it to a new triplet, and this will be addressed when the vcpkg tool changes are included.

With the November 2025 release of vcpkg.exe added, everything works without any passthrough updates to the triplets.

[walbourn]

Did a full vcpkg ci pass on the new triplets using October 2025 without the backcompat old layouts.

Did a second pass using the existing triplets using October 2025 with the backcompat present.

Same results:

SUMMARY FOR x64-xbox-scarlett
  SUCCEEDED: 1276
  BUILD_FAILED: 326
  POST_BUILD_CHECKS_FAILED: 16
  CASCADED_DUE_TO_MISSING_DEPENDENCIES: 549

This indicates to me things are correct. I'll do another run with xboxone just to be sure.

[walbourn]

Did a full vcpkg ci run on the xbox one triplet. Again, both with old layouts using original triplets against new layouts using updated triplets. Same result.

SUMMARY FOR x64-xbox-xboxone
  SUCCEEDED: 1278
  BUILD_FAILED: 324
  POST_BUILD_CHECKS_FAILED: 16
  CASCADED_DUE_TO_MISSING_DEPENDENCIES: 549

[walbourn]

Note the reason there was one more failure for Xbox Series X|S (scarlett) than Xbox One is because of a problem in XNNPACK when building for /arch:AVX2 which only scarlett uses.

[walbourn]

I've marked my updated community triplets ready for review. They work "as is" for October 2025 GDK when 'old layouts' are installed, as well as any previous GDKX (I've tested April 2025).

It is safe to merge these updates now, but the October 2025 GDK with only new layouts installed will not work until the updated November 2025 vcpkg tooling is merged as well.

[BillyONeal]

Thanks!

[walbourn]

Sanity pass with April 2025 GDK using new triplets:

SUMMARY FOR x64-xbox-scarlett
  SUCCEEDED: 1275
  BUILD_FAILED: 327
  POST_BUILD_CHECKS_FAILED: 16
  CASCADED_DUE_TO_MISSING_DEPENDENCIES: 777
  UNSUPPORTED: 316

[walbourn]

Doing one more pass with latest VCPKG tool and October 2025 GDK:

SUMMARY FOR x64-xbox-scarlett
  SUCCEEDED: 1280
  BUILD_FAILED: 320
  POST_BUILD_CHECKS_FAILED: 16
  CASCADED_DUE_TO_MISSING_DEPENDENCIES: 783
  UNSUPPORTED: 320