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

[Eli Friedman via cfe-commits]

efriedma-quic wrote:

The mangler is in clang/lib/AST/ItaniumMangle.cpp; maybe look at CXXNameMangler::mangleStandardSubstitution.

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