pthread-h: Fix definitions of types and macros on mingw.
* lib/pthread.in.h (pthread_t, pthread_attr_t, PTHREAD_CREATE_JOINABLE,
PTHREAD_CREATE_DETACHED): Define also when module 'pthread-thread' is
not in use.
(pthread_once_t, PTHREAD_ONCE_INIT): Define also when module
'pthread-once' is not in use.
(pthread_mutex_t, pthread_mutexattr_t, PTHREAD_MUTEX_INITIALIZER,
PTHREAD_MUTEX_DEFAULT, PTHREAD_MUTEX_NORMAL, PTHREAD_MUTEX_ERRORCHECK,
PTHREAD_MUTEX_RECURSIVE): Define also when module 'pthread-mutex' is not
in use.
(pthread_rwlock_t, pthread_rwlockattr_t, PTHREAD_RWLOCK_INITIALIZER):
Define also when module 'pthread-rwlock' is not in use.
(pthread_cond_t, pthread_condattr_t, PTHREAD_COND_INITIALIZER): Define
also when module 'pthread-cond' is not in use.
(pthread_key_t, PTHREAD_DESTRUCTOR_ITERATIONS): Define also when module
'pthread-tss' is not in use.
(pthread_spinlock_t): Define also when module 'pthread-spin' is not in
use.