[Bug c++/117613] [modules] using-directive not exported

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117613

--- Comment #1 from Jason Merrill <jason at gcc dot gnu.org> ---
This interferes with the using-directive used to bring the chrono literal
operators from ...::chrono_literals into std::chrono, breaking
libstdc++-prettyprinters/chrono.cc.