GnuTLS HMAC and symmetric cipher support

    * etc/NEWS: Add news for new feature.

    * doc/lispref/text.texi (GnuTLS Cryptography): Add
    documentation.

    * configure.ac: Add macros HAVE_GNUTLS3_DIGEST,
    HAVE_GNUTLS3_CIPHER, HAVE_GNUTLS3_AEAD, HAVE_GNUTLS3_HMAC.

    * src/fns.c (Fsecure_hash_algorithms): Add function to list
    supported `secure-hash' algorithms.
    (extract_data_from_object): Add data extraction function that
    can operate on buffers and strings.
    (secure_hash): Use it.
    (Fsecure_hash): Mention `secure-hash-algorithms'.

    * src/gnutls.h: Include gnutls/crypto.h.

    * src/gnutls.c (Fgnutls_ciphers, gnutls_symmetric_aead)
    (gnutls_symmetric, Fgnutls_symmetric_encrypt, Fgnutls_symmetric_decrypt)
    (Fgnutls_macs, Fgnutls_digests, Fgnutls_hash_mac, Fgnutls_hash_digest)
    (Fgnutls_available_p): Implement GnuTLS cryptographic integration.

    * test/lisp/net/gnutls-tests.el: Add tests.

1 files changed, 3 insertions, 0 deletions

diff --git a/src/lisp.h b/src/lisp.h
index 1e8ef7a449a..a5134a9532c 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -3386,6 +3386,9 @@ enum { NEXT_ALMOST_PRIME_LIMIT = 11 };
 extern EMACS_INT next_almost_prime (EMACS_INT) ATTRIBUTE_CONST;
 extern Lisp_Object larger_vector (Lisp_Object, ptrdiff_t, ptrdiff_t);
 extern void sweep_weak_hash_tables (void);
+extern const char* extract_data_from_object (Lisp_Object spec,
+                                             ptrdiff_t *start_byte,
+                                             ptrdiff_t *end_byte);
 EMACS_UINT hash_string (char const *, ptrdiff_t);
 EMACS_UINT sxhash (Lisp_Object, int);
 Lisp_Object make_hash_table (struct hash_table_test, EMACS_INT, float, float,