* inflow.c (terminal_init_inferior): Temporarily use Lynx PIDGET

	* inflow.c (terminal_init_inferior): Temporarily use Lynx PIDGET
	macro to set process groups.
	* infptrace.c (child_resume): Temporarily use Lynx PIDGET to
	specify resumption of all threads.
	* infrun.c (wait_for_inferior):  Fix handling of thread-specific
	breakpoints for systems where DECR_PC_AFTER_BREAK > 0 (ie: backup
	PC by the right amount when continuing the thread).
	* thread.c (thread_apply_command):  Add the  `thread apply'
	command to apply a given GDB command to a list of threads.