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
 ])
e/gnu/tests.scm?id=12e4ac2ccab0236b087edc8529500c07a5b2d1c1'>tree</a><a href='/guix/commit/gnu/tests.scm?id=12e4ac2ccab0236b087edc8529500c07a5b2d1c1'>commit</a><a href='/guix/diff/gnu/tests.scm?id=12e4ac2ccab0236b087edc8529500c07a5b2d1c1'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/gnu/tests.scm'>
<input type='hidden' name='id' value='12e4ac2ccab0236b087edc8529500c07a5b2d1c1'/><select name='qt'>
<option value='grep'>log msg</option>
<option value='author'>author</option>
<option value='committer'>committer</option>
<option value='range'>range</option>
</select>
<input class='txt' type='search' size='10' name='q' value=''/>
<input type='submit' value='search'/>
</form>
</td></tr></table>
<div class='path'>path: <a href='/guix/log/?id=12e4ac2ccab0236b087edc8529500c07a5b2d1c1'>root</a>/<a href='/guix/log/gnu?id=12e4ac2ccab0236b087edc8529500c07a5b2d1c1'>gnu</a>/<a href='/guix/log/gnu/tests.scm?id=12e4ac2ccab0236b087edc8529500c07a5b2d1c1'>tests.scm</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/gnu/tests.scm?id=12e4ac2ccab0236b087edc8529500c07a5b2d1c1&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2023-11-05 23:23:23 +0100'>2023-11-05</span></td><td><a href='/guix/commit/gnu/tests.scm?id=0c695bbf8dbd5a5c1224f331a78b6316bc16e4d1'>tests: Honor system and target when lowering &lt;system-test&gt;.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/tests.scm (compile-system-test): Wrap ‘system-test-value’ call in
‘mparameterize’.

Change-Id: I4be28913a86f43059b0886ad2fcf81a9c699b730
</span></span></td><td>Ludovic Courtès</td></tr>