ep_maxargs
if (plan->ep_narg == plan->ep_maxargs)
new->ep_maxargs = ARG_MAX / (sizeof (char *) + 16);
if (new->ep_maxargs > 5000)
new->ep_maxargs = 5000;
new->e_argv = emalloc((cnt + new->ep_maxargs)
if (c + new->ep_maxargs * sizeof (char *) >= MAXARG)
bufsize = MAXARG - c - new->ep_maxargs * sizeof (char *);