The Boost WINAPI partitioning scheme doesn't work for WINAPI_FAMILY_GAMES

Start by examining how WINAPI_FAMILY partitioning is handled across the winapi headers, especially crypt.hpp, bcrypt.hpp, dbghelp.hpp, jobs.hpp, priority_class.hpp, security.hpp, and shell.hpp. Compare the existing exclusions with the WINAPI_FAMILY_GAMES API set in the Windows 10 SDK 19041 or later; done means supported APIs such as SwitchToThread are available while the listed unsupported APIs remain excluded.

For Xbox development, we make use of WINAPI_FAMILY_GAMES which is supported by the Windows 10 SDK (19041) or later.

When you build with WINAPI_FAMILY=WINAPI_FAMILY_GAMES, boost ends up misconfiguring a number of APIs which are supported such as SwitchToThread. Part of the problem is that WINAPI_FAMILY_GAMES by design does NOT include everything in WINAPI_PARTITION_SYSTEM. WINAPI_FAMILY_GAMES contains many more Win32 APIs than UWP, but less than the full DESKTOP partition.

The good news is that most the Win32 APIs used by the winapi headers ARE supported for WINAPI_FAMILY_GAMES.

The only APIs that are NOT in WINAPI_FAMILY_GAMES are:

• The WinCrypt functions in crypt.hpp (bcrypt.hpp is supported instead).
• The dbghelp.hpp functions
• FlushViewOfFile
• CompareObjectHandles
• Jobs APIs in jobs.hpp
• ImpersonateNamedPipeClient. TransactNamedPipe. GetNamedPipeClientComputerNameA, GetNamedPipeClientComputerNameW
• The priority class APIs in priority_class.hpp
• The security object APIs in security.hpp
• Shell APIs in shell.hpp
• ShowWindowAsync

Fixing this is important for making the rest of boost work on the Xbox platform.

Note that for Xbox development, we officially support the MSVC VS 2017 (v141) 15.9 or later toolset as well as clang/LLVM for Windows v11 or later. Due to some link warnings with newer SDKs and Microsoft GDKs, clang/LLVM for Windows v15 or later is recommended. We also recommend VS 2019 (v142) 16.11 or later.

There's no need to access the NDA Microsoft GDK with Xbox Extensions for this work as all the relevant APIs are in the public Windows SDK (19041) or later.