[compiler-rt] [compiler-rt] Fix #122795 for solaris platforms proposal. (PR #122956)

[Rainer Orth via llvm-commits]

rorth wrote:

> Yes ideally the platform posix should take care of all posix things then the os specifics take care of native parts but I guess it s complicated unfortunately.

Right: file naming has always been a nightmare inside `compiler-rt`.  Not only might files called `*posix*` only refer to some POSIX systems, but you regularly have files called `*linux*` being used on all Unix system.  This is extremely confusing, both when working on a new port and when working on the existing code.  There's no rhyme or reason here.

https://github.com/llvm/llvm-project/pull/122956