[Windows] Implement OneCore TTS support using C++/WinRT.

[bruvzg]

Fixes #69788

Tested on Windows 11 (25H2) and Windows 10 (22H2).

Notes:

• pitch, volume, and rate are supported only on Windows 10 (1709)+
• boundary callback might be inaccurate on versions before Windows 10 (1703)
• should fall back to SAPI if no voices are found (e.g, on Wine, but both SAPI and OneCore TTS are non-functional stubs) or no API available (so might still run on Windows 8.1, not tested)

[bruvzg]

Note: Added to suppress ./core/os/spin_lock.h:96:38: warning: macro 'ATOMIC_VAR_INIT' has been marked as deprecated [-Wdeprecated-pragma] warnings, since these files require C++20. Should be removed when the rest of the code is switched to C++20.

https://github.com/godotengine/godot/pull/100749/changes#diff-43749a19ee6902b8939bb8e2cf37d6abeb8e7be9612f39b701b67a8d4146de48

[akien-mga]

Why do we need to vendor winrt headers? Aren't they part of the Windows SDK?

I'm not fond of adding 120k lines of code to solve this issue. Maybe it can be trimmed down to only the subset of headers we are using, which might be much less files?

[bruvzg]

Why do we need to vendor winrt headers? Aren't they part of the Windows SDK?

On Windows with MSVC, we do not, but it's not part of MinGW (MSYS has it as a separate package, most MinGW distributions doesn't have them at all, there are some headers of Win32 ABI namespace that supposed to be equivalent, but these are incomplete and/or broken).

For the reference, trimmed down from 1 335 940 lines (1346 files, 84 MB) of full C++/WinRT headers. Probably can be trimmed more by commenting parts of the files, but not sure if I should bother, since it's messy autogenerated headers.

[bruvzg]

For the reference, trimmed down from 1 335 940 lines (1346 files, 84 MB) of full C++/WinRT headers. Probably can be trimmed more by commenting parts of the files, but not sure if I should bother, since it's messy autogenerated headers.

Editing the files is possible but won't be maintainable.

Since it's likely we'll need WinRT API for other stuff in the future, it might be reasonable to make a separate repo with full set of pre-build headers. And add winrt build option + dependency install script for MinGW like we do with D3D12 libs/headers.

For the reference, few other uses that can benefit from WinRT API:

• show_emoji_and_symbol_picker (hack can be replaced with WinRT call).
• [Windows] Support output to HDR monitors #94496 (review) (HDR display info/events).

[bruvzg]

Since it's likely we'll need WinRT API for other stuff in the future, it might be reasonable to make a separate repo with full set of pre-build headers. And add winrt build option + dependency install script for MinGW like we do with D3D12 libs/headers.

Made an alternative version of this PR which uses build option and download script for WinRT headers - #116349

[akien-mga]

Superseded by #116349.