setinput
void setinput(char *);
setinput(inputdev);
(void)readline(setinput(mp), headline, LINESIZE, NULL);
ibuf = setinput(mp);
fp = run_editor(setinput(mp), (off_t)mp->m_size, type, readonly);
FILE *setinput(struct message *);
ibuf = setinput(mp);
ibuf = setinput(mp);
ibuf = setinput(mp);