RBF_VIDEO
static uint32_t opts = RBF_VIDEO;
if ((opts & (RBF_MUTE|RBF_SERIAL|RBF_VIDEO)) == 0)
opts |= RBF_SERIAL|RBF_VIDEO;
opts = RBF_VIDEO;
opts |= RBF_VIDEO | RBF_SERIAL;
if (opts & RBF_VIDEO)
if ((opts & RBF_VIDEO) && getc(1))