bug#27708: [PROPOSED] Simplify configuration of HAVE_GNUTLS3 etc.

[Paul Eggert]

There's only one GnuTLS, so configuring these symbols at
'configure' time is overkill.  Simplify things by moving their
configuration to src/gnutls.h.
* configure.ac (HAVE_GNUTLS3, HAVE_GNUTLS3_HMAC, HAVE_GNUTLS3_AEAD)
(HAVE_GNUTLS3_CIPHER, HAVE_GNUTLS3_DIGEST): Move these definitions
from here ...
* src/gnutls.h: ... to here, and simplify.
---
 configure.ac | 83 ------------------------------------------------------------
 src/gnutls.h | 12 +++++++--
 2 files changed, 10 insertions(+), 85 deletions(-)

diff --git a/configure.ac b/configure.ac
index 056c8c3..329a590 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2829,89 +2829,6 @@ AC_DEFUN
     [HAVE_GNUTLS=yes], [HAVE_GNUTLS=no])
   if test "${HAVE_GNUTLS}" = "yes"; then
     AC_DEFINE(HAVE_GNUTLS, 1, [Define if using GnuTLS.])
-    EMACS_CHECK_MODULES([LIBGNUTLS3], [gnutls >= 3.0.0],
-      [AC_DEFINE(HAVE_GNUTLS3, 1, [Define if using GnuTLS v3.])], [])
-
-    AC_CACHE_CHECK([for GnuTLS v3 with HMAC], [emacs_cv_gnutls3_hmac],
-      [AC_COMPILE_IFELSE(
-       [AC_LANG_PROGRAM([[
-             #include <gnutls/gnutls.h>
-             #include <gnutls/crypto.h>
-          ]], [[
-            int
-            main (void)
-            {
-              gnutls_hmac_hd_t handle;
-              gnutls_hmac_deinit (handle, NULL);
-            }
-          ]])],
-       [emacs_cv_gnutls3_hmac=yes],
-       [emacs_cv_gnutls3_hmac=no])])
-    if test "$emacs_cv_gnutls3_hmac" = yes; then
-      AC_DEFINE([HAVE_GNUTLS3_HMAC], [1],
-       [Define if using GnuTLS v3 with HMAC support.])
-    fi
-
-    AC_CACHE_CHECK([for GnuTLS v3 with AEAD], [emacs_cv_gnutls3_aead],
-      [AC_COMPILE_IFELSE(
-       [AC_LANG_PROGRAM([[
-             #include <gnutls/gnutls.h>
-             #include <gnutls/crypto.h>
-          ]], [[
-            int
-            main (void)
-            {
-              gnutls_aead_cipher_hd_t handle;
-              gnutls_aead_cipher_deinit (handle);
-            }
-          ]])],
-       [emacs_cv_gnutls3_aead=yes],
-       [emacs_cv_gnutls3_aead=no])])
-    if test "$emacs_cv_gnutls3_aead" = yes; then
-      AC_DEFINE([HAVE_GNUTLS3_AEAD], [1],
-       [Define if using GnuTLS v3 with AEAD support.])
-    fi
-
-    AC_CACHE_CHECK([for GnuTLS v3 with cipher], [emacs_cv_gnutls3_cipher],
-      [AC_COMPILE_IFELSE(
-       [AC_LANG_PROGRAM([[
-             #include <gnutls/gnutls.h>
-             #include <gnutls/crypto.h>
-          ]], [[
-            int
-            main (void)
-            {
-              gnutls_cipher_hd_t handle;
-              gnutls_cipher_encrypt2 (handle, NULL, 0, NULL, 0);
-              gnutls_cipher_deinit (handle);
-            }
-          ]])],
-       [emacs_cv_gnutls3_cipher=yes],
-       [emacs_cv_gnutls3_cipher=no])])
-    if test "$emacs_cv_gnutls3_cipher" = yes; then
-      AC_DEFINE([HAVE_GNUTLS3_CIPHER], [1],
-       [Define if using GnuTLS v3 with cipher support.])
-    fi
-
-    AC_CACHE_CHECK([for GnuTLS v3 with digest], [emacs_cv_gnutls3_digest],
-      [AC_COMPILE_IFELSE(
-       [AC_LANG_PROGRAM([[
-             #include <gnutls/gnutls.h>
-             #include <gnutls/crypto.h>
-          ]], [[
-            int
-            main (void)
-            {
-              gnutls_hash_hd_t handle;
-              gnutls_hash_deinit (handle, NULL);
-            }
-          ]])],
-       [emacs_cv_gnutls3_digest=yes],
-       [emacs_cv_gnutls3_digest=no])])
-    if test "$emacs_cv_gnutls3_digest" = yes; then
-      AC_DEFINE([HAVE_GNUTLS3_DIGEST], [1],
-       [Define if using GnuTLS v3 with digest support.])
-    fi
   fi
 
   # Windows loads GnuTLS dynamically
diff --git a/src/gnutls.h b/src/gnutls.h
index 3ec86a8..19c1686 100644
--- a/src/gnutls.h
+++ b/src/gnutls.h
@@ -23,8 +23,16 @@ along with GNU Emacs.  If not, see 
<http://www.gnu.org/licenses/>.  */
 #include <gnutls/gnutls.h>
 #include <gnutls/x509.h>
 
-#ifdef HAVE_GNUTLS3
-#include <gnutls/crypto.h>
+#if 0x030000 <= GNUTLS_VERSION_NUMBER
+# define HAVE_GNUTLS3
+# include <gnutls/crypto.h>
+#endif
+
+#if 0x030400 <= GNUTLS_VERSION_NUMBER
+# define HAVE_GNUTLS3_AEAD
+# define HAVE_GNUTLS3_CIPHER
+# define HAVE_GNUTLS3_DIGEST
+# define HAVE_GNUTLS3_HMAC
 #endif
 
 #include "lisp.h"
-- 
2.7.4