Porting B2 to Haiku OS

[fasxmut]

I'd like b2 running on more operating systems, as my favorite software build tool. Haiku is a nice os written in c++, serenityos is another nice os completely wrtten in c++. I'd like b2 build running on them.

This is a b2 haiku patch, I am not sure if it is good, but with enough test, it might be better:
http://0x0.st/-nDp.patch

[grafikrobot]

Thank you for your interest in getting B2 into other platforms :-) But I'm curios about the Haiku patch. How was it not already working on Haiku? Asking because we added some support many years ago for it.. 7f0d33a