066d05318f
Go back to activating thread debugging in new_objfile(), as well as several other places, so that thread operations such as wait() can be handled inside of the child_ops.create_inferior(). This addresses spurious SIGTRAPs at the start of debugging threaded programs. Make use of the libpthread_dbg suspend/resume interface to implement single-thread stepping. Be a little more sensible about the way IS_LWP and IS_THREAD work. Don't try to look up mutex data for a spinlock sync object (ugh, unions).