libstdc++ testsuite failures on AIX

[Jonathan Wakely]

On 04/12/18 13:57 +0000, Jonathan Wakely wrote:
>On 04/12/18 08:50 -0500, David Edelsohn wrote:
>>I'm continuing to see about 12 new testsuite failures on AIX.  They
>>all show similar characteristics complaining about mutex:
>
>I think they just need the pthread flags. It's not a priority right
>now though, since they're just test failures for new, experimental
>code.
>

And the *real* fix would be to avoid performing any synchronization
when !defined(__GTHREADS), so we don't even try to use a mutex,
because we don't need to. So "fixing" the tests would only mask that
missing feature.