* gdbthread.h (struct thread_info): Add in_infcall member.
* infcall.c (run_inferior_call): Save, set and restore in_infcall.
Remove reverences to suppress_resume_observer. Refresh
`call_thread' after returning from `proceed'.
* infcmd.c (suppress_resume_observer): Delete.
* inferior.h (suppress_resume_observer): Delete declaration.
* mi/mi-interp.c (mi_on_resume): Suppress output while calling an
inferior function.
* thread.c (set_running): Remove references to
suppress_resume_observer.
* infrun.c (struct inferior_status): Add in_infcall member.
(save_inferior_status): Save it.
(restore_inferior_status): Restore it.