[Bug libstdc++/66262] [REGRESSION] testsuite failure with libstdc++ (gcc-5) and g++-4.9 together

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66262

--- Comment #16 from Jonathan Wakely <redi at gcc dot gnu.org> ---
PR66438 has a proper analysis of this issue (and it isn't related to PR66145)