[Solaris 11.3 x86_64] Support upstream

[Buh13246]

I'm trying to build this on Solaris 11.3 to get a working rust compiler on that system, would you be interested in upstream patches? Otherwise i would just patch it locally without upstreaming.

Thanks for your work and have a nice day :)
~Buh

[thepowersgang]

There's already a bunch of patches for semi-supported platforms (e.g. FreeBSD), so go for it.

There's no garuntee that I'll keep things working, as I only really have time to test on x86_64 debian/ubuntu (and sometimes MSVC)