CTLVAR
} else if (c == CTLVAR) {
if (p[0] == CTLVAR && p[1] & VSQUOTE &&
case CTLVAR: {
case CTLVAR: /* means ~ expansion */
case CTLVAR:
USTPUTC(CTLVAR, out);
CTLVAR, VSNORMAL|VSQUOTE, '@', '=', '\0'
case CTLVAR: c = 'v'; goto backslash;
case CTLVAR+CTLQUOTE: c = 'V'; goto backslash;
case CTLVAR: