doexit
void doexit(Char **, struct command *);
{ "exit", doexit, 0, INF },
cleanup(int doexit)
if (doexit)
stack[0] = (size_t)doexit;
newstack[0] = (size_t)doexit;
void doexit(void);
newstack[pagesize/sizeof(*newstack)/2] = doexit;
goto doexit;
goto doexit;
goto doexit;
goto doexit;
doexit: