[Bug libstdc++/119647] cstdlib: error: 'aligned_alloc' has not been declared in '::'; ctime: error: 'timespec_get' has not been declared in '::'

[redi at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119647

--- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> ---
ICU is asking for an old version of POSIX, which causes macOS SDK to undeclare
functions required by C11, which means that the SDK is not compatible with
C++20 (because it assumes a C11 library).