Fix building of Shishi with libgcrypt 1.6 and later.

Patch copied from Debian:

https://anonscm.debian.org/cgit/collab-maint/shishi.git/tree/debian/patches/fix_gcrypt_detection.diff?id=948301ae648a542a408da250755aeed58a6e3542

Description: Fix autoconf gnutls detection to also accept gcrypt 1.6.
Author: Andreas Metzler <ametzler@debian.org>
Bug-Debian: http://bugs.debian.org/753150
Origin: vendor
Forwarded: no
Last-Update: 2014-07-18

--- shishi-1.0.2.orig/gl/m4/gc.m4
+++ shishi-1.0.2/gl/m4/gc.m4
@@ -12,10 +12,12 @@ AC_DEFUN([gl_GC],
   if test "$libgcrypt" != no; then
     AC_LIB_HAVE_LINKFLAGS([gcrypt], [gpg-error], [
 #include <gcrypt.h>
-/* GCRY_MODULE_ID_USER was added in 1.4.4 and gc-libgcrypt.c
-   will fail on startup if we don't have 1.4.4 or later, so
-   test for it early. */
-#if !defined GCRY_MODULE_ID_USER
+/* gc-libgcrypt.c will fail on startup if we don't have libgcrypt 1.4.4 or
+   later, test for it early. by checking for either
+   - GCRY_MODULE_ID_USER which was added in 1.4.4 and dropped in 1.6 or
+   - GCRYPT_VERSION_NUMBER which was added in 1.6.
+   */
+#if !defined GCRY_MODULE_ID_USER && !defined GCRYPT_VERSION_NUMBER
 error too old libgcrypt
 #endif
 ])
ix/tree/etc/substitutes?id=33bb89c939aee88bd211964db600df65d1b656af'>tree</a><a href='/guix/commit/etc/substitutes?id=33bb89c939aee88bd211964db600df65d1b656af'>commit</a><a href='/guix/diff/etc/substitutes?id=33bb89c939aee88bd211964db600df65d1b656af'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/etc/substitutes'>
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<div class='path'>path: <a href='/guix/log/?id=33bb89c939aee88bd211964db600df65d1b656af'>root</a>/<a href='/guix/log/etc?id=33bb89c939aee88bd211964db600df65d1b656af'>etc</a>/<a href='/guix/log/etc/substitutes?id=33bb89c939aee88bd211964db600df65d1b656af'>substitutes</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/etc/substitutes?id=33bb89c939aee88bd211964db600df65d1b656af&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2020-07-10 00:11:00 +0200'>2020-07-10</span></td><td><a href='/guix/commit/etc/substitutes?id=d283bb960f927dd5f7bb8b96bc697221e4e8ad39'>maint: Remove traces of "berlin.guixsd.org".</a><span class='msg-avail'>...<span class='msg-tooltip'>The guixsd.org domain is no longer advertised since before in 1.0.0
release in May 2019.

* etc/substitutes/berlin.guixsd.org.pub: Rename to...
* etc/substitutes/berlin.guix.gnu.org.pub: ... this.
* etc/substitutes/ci.guix.gnu.org.pub,
etc/substitutes/ci.guix.info.pub: Adjust accordingly.
* gnu/services/base.scm (%default-authorized-guix-keys): Likewise.
* guix/build/download-nar.scm (urls-for-item): Likewise.
* guix/self.scm (miscellaneous-files): Likewise.
* Makefile.am (dist_pkgdata_DATA): Likewise.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2019-06-29 14:27:22 +0200'>2019-06-29</span></td><td><a href='/guix/commit/etc/substitutes?id=3a8bfebed94ba295432da8304b7ffb4a611ef761'>etc: Remove hydra.gnu.org.pub key.</a><span class='msg-avail'>...<span class='msg-tooltip'>* etc/substitutes/hydra.gnu.org.pub: Delete file.
* guix/self.scm (miscellaneous-files): Don't install it.
* Makefile.am (dist_pkgdata_DATA): Remove it.
* gnu/services/base.scm (%default-authorized-guix-keys): Likewise.
(hydra-key-authorization): Rename to…
(substitute-key-authorization): …this.  Adjust only call site.
</span></span></td><td>Tobias Geerinckx-Rice</td></tr>
<tr><td><span title='2019-05-01 11:05:47 +0200'>2019-05-01</span></td><td><a href='/guix/commit/etc/substitutes?id=757e633d57a7b994759d69e41dd759a39f1a34ae'>build: Change default substitute server to "ci.guix.gnu.org".</a><span class='msg-avail'>...<span class='msg-tooltip'>* config-daemon.ac: Replace "ci.guix.info" with "ci.guix.gnu.org".
* doc/guix.texi (SUBSTITUTE-SERVER): Likewise.
* etc/substitutes/ci.guix.gnu.org.pub: New file.
* Makefile.am (dist_pkgdata_DATA): Add it.
* guix/scripts/build.scm (%default-log-urls): Update.
* guix/scripts/substitute.scm (%default-substitute-urls): Likewise.
* guix/store.scm (%default-substitute-urls): Likewise.
* guix/self.scm (miscellaneous-files): Add "ci.guix.gnu.org".
</span></span></td><td>Ludovic Courtès</td></tr>