RTEMS Adding UNIX98 mutex attr type support

[Jeff Johnston]

Joel Sherrill wrote:
> Hi,
>
> Simple patch to enable the UNIX98 mutex attribute
> type for RTEMS.  Everything else just ripples from there
> and the implementation is in RTEMS.
>
> 209-07-06  Joel Sherrill <joel.sherrill@oarcorp.com>
>
>    * libc/include/sys/features.h: Enable UNIX98 mutex attributes
>    for RTEMS.
>
Patch checked in.

-- Jeff J.