https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86756
--- Comment #7 from Jonathan Wakely <redi at gcc dot gnu.org> --- There are more changes needed to the library code, to stop using chdir, mkdir etc. when not supported. This was first brought up in https://gcc.gnu.org/ml/libstdc++/2019-01/msg00039.html I'm not sure how to detect whether those functions are usable though, because apparently they're declared during compilation but absent when loading libstdc++.so at runtime.
