[Solaris] replace Solaris.h hack with a set of better hacks
Summary:
Got rid of unwieldy -include Solaris.h portability solution, replacing it with interposed header and moving endian defines into Host.h.
Fixes PR28370.
Reviewers: joerg, alekseyshl, mgorny
Reviewed By: joerg
Subscribers: llvm-commits, mgorny, ro, krytarowski
Patch by Fedor Sergeev.
Differential Revision: https://reviews.llvm.org/D3413
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@306002
91177308-0d34-0410-b5e6-
96231b3b80d8