pthread_spin_destroy( ) function shall destroy the spin lock
referenced by lock and release any resources used by the lock.
Upon successful completion, these functions shall return zero;
otherwise, an error number shall be returned to indicate the error.
The functions may fail if:
[EBUSY] The implementation has detected an attempt to
initialize or destroy a spin lock while it is in use
(for example, while being used in a pthread_spin_lock( )
call) by another thread.
[EINVAL] The value specified by lock is invalid.
These functions shall not return an error code of EINTR.