[build2] guess C compiler type

[Moldmann Max]

> You could, just not easily. Specifically, you could either implement a custom build2 compilation rule for this compiler or write a wrapper that re-maps GCC options > to this compiler's interface. The first one is quite a bit of work, the second one might not be possible (I am thinking about /M* options, etc).

For the /M* options I found some counterparts for dependency generation so I might consider the wrapper solution.

> Strange, based on your previous email, it does support --version option.
> The only reason I can think of why this would fail is if it exited with non-zero code in this case (which would be pretty broken of it).

You are right --version ends with a non-zero code (1).
I guess I could address that with a wrapper as well.

As always thanks for the quick help!
Max