* threads.h, threads.c: Moved futures to their own file.

* threads.h, threads.c: Moved futures to their own file.

* Makefile.am (libguile_la_SOURCES): Added futures.c.
(DOT_X_FILES): Added futures.x.
(DOT_DOC_FILES): Added futures.doc.
(modinclude_HEADERS): Added futures.h.

* threads.c, threads.h (scm_i_create_thread): Renamed from
create_thread and made global.

* eval.c: #include "libguile/futures.h".

* init.c: #include "futures.h"
(scm_init_guile_1): Call scm_init_futures.

* stime.c (SCM_TIME_UNITS_PER_SECOND): Renamed from CLKTCK.

* stime.h (SCM_TIME_UNITS_PER_SECOND): Definition moved here.

* eval.c, eval.h (scm_trampoline_0, scm_i_call_closure_0): New
functions.

* eval.c (scm_trampoline_1): Fixed arguments test for closures.