Adapting cppExamples for Windows build

[morteham]

• Avoid conflict with definition of _CONCAT in xatomic.h
• Set CXX flags for MSVC

[vegardjervell]

Nice!

Could you add a note in the C++ "getting started" helper (docs/vCurrent/getting_started_cpp.md) mentioning anything people need to take into account when using the C++ wrapper?

It would probably also be nice to add a workflow step to the unittests workflow equivalent to Run cppExamples on Linux/macOS that just builds and runs the examples on windows so that we can be sure they stay fixed in the future :)

[morteham]

Updated docs and unittets

[vegardjervell]

It looks like the Ubuntu GitHub runner doesn't have ninja installed. I can see from the cibuildwheel workflow that CIBW fetches ninja as part of its setup process. I don't know why this is suddenly breaking the ubuntu build when it didn't before, but maybe there's some change in some package (or in scipy-build-core) that now means we need to install ninja to the ubuntu runner before building the wheel for testing.

I tried pushing a fix now, I'll merge if it works, otherwise I'll probably just need to tweak a bit for the ninja installation to work properly (ensure stuff is correctly added to PATH etc.)

[vegardjervell]

Nice stuff, we ballin'