ntsync: Introduce NTSYNC_IOC_MUTEX_KILL.

This does not correspond to any NT syscall. Rather, when a thread dies, it
should be called by the NT emulator for each mutex, with the TID of the dying
thread.

NT mutexes are robust (in the pthread sense). When an NT thread dies, any
mutexes it owned are immediately released. Acquisition of those mutexes by other
threads will return a special value indicating that the mutex was abandoned,
like EOWNERDEAD returned from pthread_mutex_lock(), and EOWNERDEAD is indeed
used here for that purpose.

Signed-off-by: Elizabeth Figura <zfigura@codeweavers.com>
Link: https://lore.kernel.org/r/20241213193511.457338-8-zfigura@codeweavers.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>