I stand corrected (although I still can't speak to what the VC++ compilers do): I somehow thought there were "bootstrapping" headers that were silently included

I stand corrected (although I still can't speak to what the VC++ compilers do): I somehow thought there were "bootstrapping" headers that were silently included with a compiler invocation, but were still subject to exclusion through various "-nostdinc" and "-nobuiltininc" style "just preprocess the given C source, without respect to the filesystem". But in the few minutes I spent futzing around with clang-15 I was unable to find a counter example, and sure enough even running strings on libclang-cpp coughs up one I would have thought for sure was coming from such a system header $ grep -rl __GNUC_PATCHLEVEL__ $HOMEBREW_CELLAR/llvm/15.0.6/lib/libclang-cpp.so.15 /home/linuxbrew/.linuxbrew/Cellar/llvm/15.0.6/lib/libclang-cpp.so.15 I'm sorry for the noise