* inflow.h (our_process_group): Remove declaration.

	* inflow.h (our_process_group): Remove declaration.
	(inferior_process_group): Delete global variable declaration.
	(inferior_process_group): New function declaration.
	* inflow.c: Include observer.h.
	(inferior_ttystate, our_ttystate, tflags_inferior, tflags_ours):
	Delete.
	(struct terminal_info): New struct.
	(our_terminal_info): New global.
	(inferior_process_group): New function.
	(inferior_thisrun_terminal): Extend description comment.
	(gdb_has_a_terminal): Adjust to write to our_terminal_info fields
	instead of globals.
	(terminal_init_inferior_with_pgrp): Adjust to per-inferior
	terminal settings.
	(terminal_inferior): Ditto.
	(terminal_ours_1): Ditto.
	(inflow_new_inferior, inflow_inferior_exit): New functions.
	(child_terminal_info): Adjust to per-inferior terminal settings.
	(osig_set): New global.
	(set_sigint_trap): Adjust to per-inferior terminal settings.  Set
	or clear `osig_set' accordingly.
	(clear_sigint_trap): Check `osig_set' to decide wheater to restore
	SIGINT handler, instead of checking the current inferior (which
	may be none).
	(_initialize_inflow): Attach inflow_new_inferior and
	inflow_inferior_exit to the "new_inferior" and "inferior_exit"
	notifications, respectively.
	* inferior.h (struct terminal_info): Forward declare.
	(struct inferior): Add `terminal_info' field.
	* inferior.c (delete_inferior_1): Notify the inferior_exit
	observers before removing the inferior from the lists and deleting
	it.
	* inf-ptrace.c (inf_ptrace_stop): `inferior_process_group' is now
	a function instead of a variable.  Adjust.
	* procfs.c (procfs_stop): Ditto.