cross: Move Solaris API64 defines to common

[imp]

Summary

off64_t is needed for both Linux and MacOS, so move them to the common
area.

Pull Request: https://github.com/freebsd/freebsd-src/pull/1066

Test Plan

I'd like to slice PR-1066 up a bit differently so we can get bits in that we agree on while working on others. The current commits aren't well suited for that, so I'm doing this Phab review to get things started. (also, I can push to my github and do pull requests to run testing too). I'm open to other ways too, but I thought I'd start here to get it rolling because as it is PR-1066 is just too big and disconnected to review effectively.

[imp]

My mac still builds with this. My ubuntu 22.4 is still chugging away at it

[jrtc27]

Though please mention that it's needed for musl in the commit message, otherwise it's not clear why we've been fine without this diff for years

[imp]

59aa64914aeb1b2cccc0d4fc39ead2ee159a1e5b landed this. Forgot to update the commit message so this would autoclose.