S_DOALTERNATE
if ((search & S_DOALTERNATE) != 0) {
if ((search & S_DOALTERNATE) != 0) {
search &= ~S_DOALTERNATE;
if ((search & S_DOALTERNATE) != 0 && --alt_untrusted > 0)
if (!may_alternate || (search & S_DOALTERNATE) != 0 || ctx->num_untrusted < 2)
search |= S_DOALTERNATE;