[Bug libstdc++/95545] thread:: conflicts with std::thread

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95545

--- Comment #6 from Jonathan Wakely <redi at gcc dot gnu.org> ---
See
https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#Rs-using
in the C++ Core Guidelines.