Charles Brunet

Could you please squash all your commits into one?

@dcbaker I think this one is ready

Do not forget to update documentation and to add a release snippet.

There is a small typo in the commit message: `shutil.whichk()`

> This should probably raise a MesonException or appropriate child exception when the compiler doesn't have a Microsoft CRT, to prevent people from assuming its meaning. It should only be...

@eli-schwartz Do you still have concerns about this PR?

> Why does this add 22 new tests? Because it tests combinations of `b_vscrt` and `buildtype`. > What happens on non-Windows platforms? It depends whether the compiler implements `get_crt_compile_args` or...

For the test, I'm testing that each `buildtype` gives the right crt when `b_vscrt` is `from_buildtype` or `static_from_buildtype` (5 build types (custom does not apply) x 2 `b_vscrt` = 10...

> I would like to see comparable test coverage implemented in much less test runtime. I suspect it can be done. I agree... But I guess the only way would...

@xclaesse I saw it is you who added the ml compiler. Could you please check the first commit? I *think* we must return the proper `/md`, etc. switch instead of...