fix broken UWP build

[Dargun]

Summary

This PR fixes a regression introduced in #33, which unintentionally broke functionality added in #34.

Details

When using:

set(CMAKE_SYSTEM_NAME WindowsStore)

the variable CMAKE_SYSTEM_PROCESSOR is always empty. Because of this, UWP builds can only rely on CMAKE_GENERATOR_PLATFORM.

This PR adds support for using both variables to cover all cases, restoring proper behavior and ensuring UWP builds work again.

Additional Improvements

• Replaced the obsolete if(WINDOWS_STORE) condition with the correct:

  if("${CMAKE_SYSTEM_NAME}" STREQUAL "WindowsStore")

• Successfully rebuilt UWP with these changes to confirm everything works as expected.

[Dargun]

It would be helpful to add a UWP build check here as well 😉

[jimmy-park]

I think CMAKE_SYSTEM_PROCESSOR should be set along with CMAKE_SYSTEM_NAME in the toolchain file.

By the way I don't know why you suggest "${CMAKE_SYSTEM_NAME}" STREQUAL "WindowsStore" instead of the much simpler WINDOWS_STORE. And it is not obsolete.

[Dargun]

I think CMAKE_SYSTEM_PROCESSOR should be set along with CMAKE_SYSTEM_NAME in the toolchain file.

I’m relying solely on Polly, and from what I understand these two definitions are sufficient:

set(CMAKE_SYSTEM_NAME WindowsStore)
set(CMAKE_SYSTEM_VERSION 10.0)

[Dargun]

By the way I don't know why you suggest "${CMAKE_SYSTEM_NAME}" STREQUAL "WindowsStore" instead of the much simpler WINDOWS_STORE. And it is not obsolete.

Yeah, sorry — I forgot that this works too. I always use "${CMAKE_SYSTEM_NAME}" STREQUAL "WindowsStore" in my codebase, but using WINDOWS_STORE is much cleaner. 😉
i can change it back ;)

[jimmy-park]

I’m relying solely on Polly, and from what I understand these two definitions are sufficient:

set(CMAKE_SYSTEM_NAME WindowsStore)
set(CMAKE_SYSTEM_VERSION 10.0)

Setting CMAKE_SYSTEM_PROCESSOR in your toolchain file is the official way to specify the target system.
Please see the related CMake document.

https://cmake.org/cmake/help/latest/variable/CMAKE_SYSTEM_PROCESSOR.html