https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104123
--- Comment #3 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:f5c50748f361841c30d95c1743f040f2f8ec831c commit r12-6750-gf5c50748f361841c30d95c1743f040f2f8ec831c Author: Jonathan Wakely <jwak...@redhat.com> Date: Wed Jan 19 17:39:00 2022 +0000 libstdc++: Include <stddef.h> for size_t and ptrdiff_t [PR104123] libstdc++-v3/ChangeLog: PR libstdc++/104123 * testsuite/29_atomics/headers/stdatomic.h/c_compat.cc: Include <stddef.h>.