[clang] [clang] Handle tm mangling on Solaris in PPMacroExpansion.cpp (PR #100724)

[Aaron Ballman via cfe-commits]

https://github.com/AaronBallman approved this pull request.

LGTM; if we find a better approach post-commit, this is easy enough to remove. Thanks!

https://github.com/llvm/llvm-project/pull/100724