https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119050
--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> --- (In reply to Andrew Pinski from comment #0) > Or maybe -Wundef can be refinded not to warn about the C++ feature macros ... Even with that change, it would be a big project to clean up hundreds of other With #include <bits/stdc++.h> there are 240+ warnings that aren't __cpp_xxx or __glibcxx_xxx feature test macros. We've never been -Wundef clean, and I don't see much reason to change that. If you don't use -Wsystem-headers, it's not a problem.
