gnu: gnutls: Patch bug in 'set-session-server-name!'.

* gnu/packages/patches/gnutls-server-name-fix.patch: New file.
* gnu/packages/gnutls.scm (gnutls)[source]: Use it.
* gnu-system.am (dist_patch_DATA): Add it.

gnu-system.am

@@ -344,6 +344,7 @@ dist_patch_DATA =						\
   gnu/packages/patches/glibc-ldd-x86_64.patch			\
   gnu/packages/patches/gnunet-fix-scheduler.patch		\
   gnu/packages/patches/gnunet-fix-tests.patch    		\
+  gnu/packages/patches/gnutls-server-name-fix.patch		\
   gnu/packages/patches/gobject-introspection-cc.patch		\
   gnu/packages/patches/grub-gets-undeclared.patch		\
   gnu/packages/patches/gstreamer-0.10-bison3.patch		\

gnu/packages/gnutls.scm

@@ -74,7 +74,8 @@ specifications.")
                              "/gnutls-" version ".tar.xz"))
              (sha256
               (base32
-               "1krx33ab2ijwfz71f1ba8labxfsic7jhlhv6rvjsyw566jj9a3d2"))))
+               "1krx33ab2ijwfz71f1ba8labxfsic7jhlhv6rvjsyw566jj9a3d2"))
+             (patches (list (search-patch "gnutls-server-name-fix.patch")))))
     (build-system gnu-build-system)
     (native-inputs
      `(("pkg-config" ,pkg-config)))

gnu/packages/patches/gnutls-server-name-fix.patch

@@ -0,0 +1,17 @@
+Fix a typo introduced in the first series implementing
+'set-session-server-name!' whereby the trailing nul character would
+be passed on the wire, thereby breaking connections.
+
+diff --git a/guile/src/core.c b/guile/src/core.c
+index 82fd573..2778205 100644
+--- a/guile/src/core.c
++++ b/guile/src/core.c
+@@ -719,7 +719,7 @@ SCM_DEFINE (scm_gnutls_set_session_server_name_x, "set-session-server-name!",
+   c_name = scm_to_locale_string (name);
+ 
+   err = gnutls_server_name_set (c_session, c_type, c_name,
+-				strlen (c_name) + 1);
++				strlen (c_name));
+   free (c_name);
+ 
+   if (EXPECT_FALSE (err != GNUTLS_E_SUCCESS))