trace: split into several functions

This change moves the main loop back to main() and splits trace()
into several functions.  There are no algorithmic changes.

* strace.c (print_debug_info, maybe_allocate_tcb, maybe_switch_tcbs,
print_signalled, print_exited, print_stopped, startup_tcb): New
functions.
(trace) Use them.  Move the main loop ...
(main): ... here.
1 file changed