libmbedtls: Support OpenSSH-compatible AES-GCM ciphers using mbedTLS

Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>

src/libgcrypt.c

@@ -31,6 +31,7 @@
 #include "libssh/crypto.h"
 #include "libssh/wrapper.h"
 #include "libssh/string.h"
+#include "libssh/misc.h"
 
 #ifdef HAVE_LIBGCRYPT
 #include <gcrypt.h>
@@ -429,19 +430,6 @@ aes_aead_get_length(struct ssh_cipher_struct *cipher,
     return SSH_OK;
 }
 
-/* Increment 64b integer in network byte order */
-static void
-uint64_inc(unsigned char *counter)
-{
-    int i;
-
-    for (i = 7; i >= 0; i--) {
-        counter[i]++;
-        if (counter[i])
-          return;
-    }
-}
-
 static void
 aes_gcm_encrypt(struct ssh_cipher_struct *cipher,
                 void *in,