[PATCH roland/sem_post] BZ#18434: Fix sem_post EOVERFLOW check for [!__HAVE_64B_ATOMICS].

[Torvald Riegel]

On Tue, 2015-05-19 at 15:11 -0700, Roland McGrath wrote:
> This bug is a regression introduced by the 2.21 semaphore rewrite.
> It affects all machines without __HAVE_64B_ATOMICS.
> 
> Tested i686-linux-gnu and arm-nacl, where the new test case fails before
> the fix and passes after it.  I didn't test the sparc32 code, but the bug
> and the fix are the same as in the generic code.
> 
> This seems appropriate for a 2.21 backport, and I've marked the bug that
> way (I've just added the glibc_2.21 keyword since we didn't have one yet).

Ouch :(  Thanks for fixing this!