Lie about futex_atomic_cmpxchg_inatomic kernel support.

Lie about futex_atomic_cmpxchg_inatomic kernel support.

Bug-Ubuntu: https://launchpad.net/bugs/1436162
Bug-Debian: https://bugs.debian.org/788799
Last-Update: 2015-03-25

In past versions of glibc, we incorrectly assumed all ARM kernels
in all configurations supported futex_atomic_cmpxchg_inatomic. This
was clearly a lie, however it was a lie that we relied on, because
the fallback implementation appears to not play nicely with certain
applications like pulseaudio.  Restore the lie for kernels > 2.6.32
and plug our ears and scream "LA LA LA" about how wrong this is.

Gbp-Pq: Topic arm
Gbp-Pq: Name local-arm-futex.diff