WIP: Add VK_EXT_external_memory_metal

[aitor-lunarg]

No description provided.

[kocdemir]

@aitor-lunarg , the extension is working fine for us so far with the additional handling of the case I've mentioned in the other comment. Would be great to see this merged in soon, but otherwise how can we get this external dependencies merged into Vulkan-Headers to avoid issues with the future updates on MoltenVK?

[aitor-lunarg]

The main issue is that until the spec PR is not approved and merged, Vulkan-Headers cannot be updated with the xml data that contains the extension. Once the spec PR is merged then I will be able to start merging all other repositories that rely on Vulkan-Headers (which are VVL, CTS and MoltenVK). It's pretty much a domino effect, but as mentioned until the spec PR is approved and merged, the only thing I can do is update the Vulkan-Headers repository this change is pointing to so it is based on top of current MoltenVK's hash with the patch applied on top. If there's anything else I could do to facilitate pulling this change do let me know. Otherwise, I'll just update this PR once MoltenVK pulls new headers so there are not conflicts.

[billhollings]

@aitor-lunarg What's the status of this PR?

1. Do you expect to push an MR to the Vulkan Headers repo (either GitHub or GitLab) soon?
2. How comfortable are we with this PR now? Based on feedback here, looks like it's pretty close.

[aitor-lunarg]

1. Do you expect to push an MR to the Vulkan Headers repo (either GitHub or GitLab) soon?

I am waiting for the spec PR to be approved and merged. This will trigger a domino effect and the required changes for Vulkan Headers repo will happen some time after spec merge. Once that happens, I will modify this PR to point to the right Vulkan Headers hash.

2. How comfortable are we with this PR now? Based on feedback here, looks like it's pretty close.

I believe it works for our use case, so right now I'm just waiting for the spec PR to be approved