mention sntrup761x25519-sha512 in manpages

Spotted by Colin Watson

kex.c

@@ -113,6 +113,8 @@ static const struct kexalg kexalgs[] = {
 	{ KEX_CURVE25519_SHA256, KEX_C25519_SHA256, 0, SSH_DIGEST_SHA256 },
 	{ KEX_CURVE25519_SHA256_OLD, KEX_C25519_SHA256, 0, SSH_DIGEST_SHA256 },
 #ifdef USE_SNTRUP761X25519
+	{ KEX_SNTRUP761X25519_SHA512_IANA, KEX_KEM_SNTRUP761X25519_SHA512, 0,
+	    SSH_DIGEST_SHA512 },
 	{ KEX_SNTRUP761X25519_SHA512, KEX_KEM_SNTRUP761X25519_SHA512, 0,
 	    SSH_DIGEST_SHA512 },
 #endif

kex.h

@@ -63,6 +63,7 @@
 #define	KEX_CURVE25519_SHA256		"curve25519-sha256"
 #define	KEX_CURVE25519_SHA256_OLD	"[email protected]"
 #define	KEX_SNTRUP761X25519_SHA512	"[email protected]"
+#define	KEX_SNTRUP761X25519_SHA512_IANA	"sntrup761x25519-sha512"
 
 #define COMP_NONE	0
 /* pre-auth compression (COMP_ZLIB) is only supported in the client */

m4/openssh.m4

@@ -20,18 +20,24 @@ char *f2(char *s, ...) {
 	va_end(args);
 	return strdup(ret);
 }
+const char *f3(int s) {
+	return s ? "good" : "gooder";
+}
 int main(int argc, char **argv) {
-	(void)argv;
 	char b[256], *cp;
+	const char *s;
 	/* Some math to catch -ftrapv problems in the toolchain */
 	int i = 123 * argc, j = 456 + argc, k = 789 - argc;
 	float l = i * 2.1;
 	double m = l / 0.5;
 	long long int n = argc * 12345LL, o = 12345LL * (long long int)argc;
+	(void)argv;
 	f(1);
-	snprintf(b, sizeof b, "%d %d %d %f %f %lld %lld\n", i,j,k,l,m,n,o);
+	s = f3(f(2));
+	snprintf(b, sizeof b, "%d %d %d %f %f %lld %lld %s\n", i,j,k,l,m,n,o,s);
 	if (write(1, b, 0) == -1) exit(0);
-	cp = f2("%d %d %d %f %f %lld %lld\n", i,j,k,l,m,n,o);
+	cp = f2("%d %d %d %f %f %lld %lld %s\n", i,j,k,l,m,n,o,s);
+	if (write(1, cp, 0) == -1) exit(0);
 	free(cp);
 	/*
 	 * Test fallthrough behaviour.  clang 10's -Wimplicit-fallthrough does

myproposal.h

@@ -25,6 +25,7 @@
  */
 
 #define KEX_SERVER_KEX	\
+	"sntrup761x25519-sha512," \
 	"[email protected]," \
 	"curve25519-sha256," \
 	"[email protected]," \

ssh_config.5

@@ -1267,6 +1267,7 @@ character, then the specified algorithms will be placed at the head of the
 default set.
 The default is:
 .Bd -literal -offset indent
+sntrup761x25519-sha512,
 [email protected],
 curve25519-sha256,[email protected],
 ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,

sshd_config.5

@@ -1037,11 +1037,14 @@ ecdh-sha2-nistp384
 .It
 ecdh-sha2-nistp521
 .It
+sntrup761x25519-sha512
+.It
 [email protected]
 .El
 .Pp
 The default is:
 .Bd -literal -offset indent
+sntrup761x25519-sha512,
 [email protected],
 curve25519-sha256,[email protected],
 ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,