https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99995
--- Comment #1 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Jonathan Wakely <r...@gcc.gnu.org>: https://gcc.gnu.org/g:29046e02b84a16b6315d952d7f76c502d0d021c2 commit r11-8127-g29046e02b84a16b6315d952d7f76c502d0d021c2 Author: Jonathan Wakely <jwak...@redhat.com> Date: Mon Apr 12 11:12:47 2021 +0100 libstdc++: Fix test that fails in C++20 mode [PR 99995] The 17_intro/headers/c++1998/49745.cc test fails for C++20 mode with PCH enabled, because PCH makes it include <bits/stdc++.h>, which includes <atomic>, and that includes <unistd.h> in C++20 mode. The <unistd.h> dependency should go away when C++20 atomic waiting is stable, but will probably remain while the feature is experimental. Change the test to always include <bits/stdc++.h>, and XFAIL for C++20 and later. libstdc++-v3/ChangeLog: PR libstdc++/99995 * testsuite/17_intro/headers/c++1998/49745.cc: Include all standard headers and XFAIL for effective-target c++20.