RE: __ghtread_recursive_mutex_destroy missing

[Nicola Pero]

> The gthreads portability layer is missing a function for destroying a
> __ghtread_recursive_mutex object.
>
> For pthreads-based models the recursive mutex type is the same as the
> normal mutex type so __gthread_mutex_destroy handles both, but they're
> distinct types for (at least) gthr-win32.h, so we can't properly
> cleanup recursive mutexes in libstdc++
>
> Any objections if I prepare a patch to add
> __gthread_recursive_mutex_destroy to each gthr header?

It makes sense.  libobjc could use these as well; all mutexes in libobjc
are recursive mutexes.  At the moment libobjc uses __gthread_objc_mutex_xxx
and similar, but it should probably move to use __gthread_recursive_mutex_xxx.

Thanks