x_del_back
kb_add(x_del_back, CTRL('?'), 0);
kb_add(x_del_back, CTRL('H'), 0);
static int x_del_back(int);
kb_add(x_del_back, ec->erase, 0);
{ x_del_back, "delete-char-backward", XF_ARG },
else if (f == x_del_back) {