CHN_F_VCHAN_ADAPTIVE
if (!(c->flags & CHN_F_VCHAN_ADAPTIVE)) {
if (c->flags & CHN_F_VCHAN_ADAPTIVE) {
if (!(c->flags & CHN_F_VCHAN_ADAPTIVE) ||
#define CHN_F_VCHAN_DYNAMIC (CHN_F_VCHAN_PASSTHROUGH | CHN_F_VCHAN_ADAPTIVE)
else if (*vchanmode & CHN_F_VCHAN_ADAPTIVE)
dflags = CHN_F_VCHAN_ADAPTIVE;