(lin_lwp_wait): Block SIGCHLD here if it isn't already blocked.
(lin_lwp_mourn_inferior): Restore the origional signal mask, and
reset the mask of blocked signals.
(_initialize_lin_lwp): Don't block SIGCHLD here, but do initialize
suspend_mask and blocked_mask. This makes us pass
gdb.base/sigall.exp for Linux/x86 now.
(lin_thread_get_thread_signals): Treat the LinuxThreads "cancel"
signal similarly to SIGCHLD in the generic code. Avoids GDB being
terminated by a Real-time signal.
GET_THREAD_SIGNALS): New defines.
* config/i386/linux.mh (NATDEPFILES): Remove lin-thread.o and
linux-threads.o. Add proc-service.o, thread-db.o and lin-lwp.o.
* proc-service.c: New file.
* thread-db.c: New file.
* lin-lwp.c: New file.
