Add the Solaris support directory to the header search when using libc++.

Unconditionally define __C99FEATURES__ when using C++ on Solaris.  This is a
(hopefully temporary) work around for libc++ exposing C99-but-not-C++98
features in C++98 mode.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@151889 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed