* configure.in: Remove PTH_ALLOW.

* configure.in: Remove PTH_ALLOW.
* cygwin.din: Remove @PTH_ALLOW@ prefixes to pthread functions.  Add new
pthread exports.
* pthread.cc: New wrapper functions for the above new exports.
* sched.cc (valid_sched_parameters): New function.
(sched_setparam): Use it.
(sched_set_thread_priority): New function.  Used by pthread_sched*.
* thread.cc (pthread_key_destructor::InsertAfter): New function.
(pthread_key_destructor::UnlinkNext): New function.
(pthread_key_destructor::Next): New function.
(pthread_key_destructor_list::Insert): New function.
(pthread_key_destructor_list::Remove): New function.
(pthread_key_destructor_list::Pop): New function.
(pthread_key_destructor::pthread_key_destructor): New function.
(pthread_key_destructor_list::IterateNull): New function.
(MTinterface::Init): Initialise new member.
(pthread::pthread): Initialise new members.
(pthread::create): Copy new attributes.  Set the new thread priority.
(pthread_attr::pthread_attr): Initialise new members.
(pthread_key::pthread_key): Setup destructor function.
(pthread_key::~pthread_key): Remove destructor function.
(pthread_mutexattr::pthread_mutexattr): New function.
(pthread_mutexattr::~pthread_mutexattr): New function.
(__pthread_once): New function.
(__pthread_cleanup): New function.
(__pthread_cancel): New function.
(__pthread_setcancelstate): New function.
(__pthread_setcanceltype): New function.
(__pthread_testcancel): New function.
(__pthread_attr_getinheritsched): New function.
(__pthread_attr_getschedparam): New function.
(__pthread_attr_getschedpolicy): New function.
(__pthread_attr_getscope): New function.
(__pthread_attr_setinheritsched): New function.
(__pthread_attr_setschedparam): New function.
(__pthread_attr_setschedpolicy): New function.
(__pthread_attr_setscope): New function.
(__pthread_exit): Call any key destructors on thread exit.
(__pthread_join): Use the embedded attr values.
(__pthread_detach): Use the embedded attr values.
(__pthread_getconcurrency): New function.
(__pthread_getschedparam): New function.
(__pthread_key_create): Pass the destructor on object creation.
(__pthread_key_delete): Correct incorrect prototype.
(__pthread_setconcurrency): New function.
(__pthread_setschedparam): New function.
(__pthread_cond_timedwait): Support static mutex initialisers.
(__pthread_cond_wait): Ditto.
(__pthread_mutex_getprioceiling): New function.
(__pthread_mutex_lock): Support static mutex initialisers.
(__pthread_mutex_trylock): Ditto.
(__pthread_mutex_unlock): Ditto.
(__pthread_mutex_destroy): Ditto.
(__pthread_mutex_setprioceiling): New function.
(__pthread_mutexattr_getprotocol): New function.
(__pthread_mutexattr_getpshared): New function.
(__pthread_mutexattr_gettype): New function.
(__pthread_mutexattr_init): New function.
(__pthread_mutexattr_destroy): New function.
(__pthread_mutexattr_setprotocol): New function.
(__pthread_mutexattr_setprioceiling): New function.
(__pthread_mutexattr_getprioceiling): New function.
(__pthread_mutexattr_setpshared): New function.
(__pthread_mutexattr_settype): New function.  Remove stubs for non MT_SAFE
compilation.
* thread.h: Remove duplicate #defines.  Add prototypes for new functions in
thread.cc.
(pthread_key_destructor): New class.
(pthread_key_destructor_list): New class.
(pthread_attr): Add new members.
(pthread): Remove members that are duplicated in the pthread_attr class.
(pthread_mutex_attr): Add new members.
(pthread_once): New class.
* include/pthread.h: Add prototypes for new functions exported from
cygwin1.dll.  Remove typedefs.
* include/sched.h: Add prototypes for new functions in sched.cc.
* include/cygwin/types.h: Add typedefs from pthread.h