[Bug libstdc++/86756] Don't define __cpp_lib_filesystem unless --enable-libstdcxx-filesystem-ts

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86756

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2018-07-31
     Ever confirmed|0                           |1

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Same for <experimental/filesystem> and __cpp_lib_experimental_filesystem.