[cppwinrt] Update to version 2.0.201008.2

[Link1J]

Updates C++/WinRT (cppwinrt) to version 2.0.201008.2. This required a new way of installing it because the repository no longer includes pre-built header files. This put more restrictions on what triplets are supported, limiting it to Windows only. It also now requires a version of the Windows SDK to be installed. With the large change needed to get the header files, a CMakeLists.txt was added, as to allow easier usage to with cmake.

This is a second attempt at doing this update. The first attempt was #14037

Which triplets are supported/not supported?
x86-windows, x64-windows, arm-uwp, x64-uwp, arm64-windows, and x64-windows-static are supported.

Does your PR follow the maintainer guide? Yes, including a manifest file.

[Link1J]

Is cppwinrt using a latest Windows SDK on the system fine? It may be an issue as two developers may not have the same latest Windows SDK installed.

[BillyONeal]

Is cppwinrt using a latest Windows SDK on the system fine? It may be an issue as two developers may not have the same latest Windows SDK installed.

You mean due to the -input sdk ?

[Link1J]

Correct.

[BillyONeal]

@Link1J I see... hmmmm I'm not sure. Normally it would be fine but I want to talk to the binary caching expert(s).

[BillyONeal]

Now that cppwinrt is in the Windows SDK itself would the right thing be to remove/deprecate this port entirely?

[BillyONeal]

@ras0219 / @ras0219-msft is going to ask around and see what needs to be done here.

[BillyONeal]

In the future we might want some sort of feature which consumes .winmds and runs the cppwinrt tools against them. However, for the system .winmds, as this port provides, the generated content would be identical to that already included in the PSDK. As as a result for now we should change this port to be empty, and emit a message explaining that the user needs a recent enough Windows SDK (similar to our atlmfc port). Would you be willing to make such changes @Link1J ?

[Link1J]

I am.

[BillyONeal]

@Link1J Thanks again for your contribution! This should land shortly....

[BillyONeal]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[JackBoosY]

LGTM.

[BillyONeal]

Thanks for your contribution!

[JackBoosY]

Issue #23249 requests to update this port and use the github repo instead of Windows SDK.
@BillyONeal what do you think about?

[BillyONeal]

I believe the cppwinrt owners still want the Windows SDK to be the "official" deployment mechanism. I can ask

[kennykerr]

Using the version of https://github.com/microsoft/cppwinrt in the Windows SDK is discouraged. The Windows SDK ships very infrequently, so you can often end up with a very old version. I recommend you grab the latest version here:

https://www.nuget.org/packages/Microsoft.Windows.CppWinRT/

This is the only cppwinrt package we publish and maintain.

[walbourn]

@BillyONeal I'm working on an improved cppwinrt port that pulls down the cppwinrt compiler from the published NuGet and then generates the projections from the installed Windows SDK. This should result in a much more useful port.