* coop.c (coop_mutex_init, coop_mutex_lock, coop_mutex_unlock,

* coop.c (coop_mutex_init, coop_mutex_lock, coop_mutex_unlock,
coop_condition_variable_init, coop_condition_variable_wait,
coop_condition_variable_signal): Changed return type from `void'
to `int'.  This is to adhere closer to the pthreads interface.
This, in turn, is part of an attempt to provide C versions of the
mutex and condition variable primitives which can be part of a
frontend to COOP or pthreads.

* coop.c (coop_mutex_destroy, coop_condition_variable_wait_mutex,
coop_condition_variable_destroy): New functions.

* coop-threads.c (scm_wait_condition_variable): Use
coop_condition_variable_wait_mutex.

* coop-threads.h, coop-defs.h (coop_q_t, coop_m, coop_c):
Definitions moved to coop-defs.h.

* coop-defs.h (scm_mutex_init, scm_mutex_lock, scm_mutex_unlock,
scm_mutex_destroy, scm_cond_init, scm_cond_wait, scm_cond_signal,
scm_cond_destroy): New C interface to mutecis and cond vars.