sshsig_dearmor
ASSERT_INT_EQ(sshsig_dearmor(sig, &rawsig), 0);
if ((r = sshsig_dearmor(abuf, &sigbuf)) != 0) {
if ((r = sshsig_dearmor(abuf, &sigbuf)) != 0) {
int sshsig_dearmor(struct sshbuf *sig, struct sshbuf **out);