https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64438
--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> --- That's strange, it should only affect targets that define _GLIBCXX_HAVE_BROKEN_VSWPRINTF i.e. only mingw What are the full errors in the libstdc++-v3/testsuite/libstdc++.log file?
