This fixes a regression introduced in 1.8.0 where libssh2 fails to build
with the gcrypt backend.

Upstream bug URL:

https://github.com/libssh2/libssh2/issues/150

Patch copied from upstream source repository:

https://github.com/libssh2/libssh2/commit/ced924b78a40126606797ef57a74066eb3b4b83f

From ced924b78a40126606797ef57a74066eb3b4b83f Mon Sep 17 00:00:00 2001
From: Sergei Trofimovich <siarheit@google.com>
Date: Mon, 31 Oct 2016 09:04:33 +0000
Subject: [PATCH] acinclude.m4: fix ./configure --with-libgcrypt

diff --git a/acinclude.m4 b/acinclude.m4
index 734ef07..c78260c 100644
--- a/acinclude.m4
+++ b/acinclude.m4
@@ -412,9 +412,9 @@ AC_DEFUN([LIBSSH2_CHECKFOR_GCRYPT], [
 
   old_LDFLAGS=$LDFLAGS
   old_CFLAGS=$CFLAGS
-  if test -n "$use_libgcrypt" && test "$use_libgcrypt" != "no"; then
-    LDFLAGS="$LDFLAGS -L$use_libgcrypt/lib"
-    CFLAGS="$CFLAGS -I$use_libgcrypt/include"
+  if test -n "$with_libgcrypt_prefix" && test "$use_libgcrypt" != "no"; then
+    LDFLAGS="$LDFLAGS -L$with_libgcrypt_prefix/lib"
+    CFLAGS="$CFLAGS -I$with_libgcrypt_prefix/include"
   fi
   AC_LIB_HAVE_LINKFLAGS([gcrypt], [], [
     #include <gcrypt.h>
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<tr><td><span title='2018-02-28 22:24:42 +0200'>2018-02-28</span></td><td><a href='/guix/commit/gnu/packages/libunistring.scm?id=652cad85fa10e792bd9c4aa6e93ed9d4064bbfb2'>gnu: libunistring: Update to 0.9.9.</a><span class='msg-avail'>...</span></td><td>Efraim Flashner</td></tr>
<tr><td><span title='2017-12-03 16:36:43 +0100'>2017-12-03</span></td><td><a href='/guix/commit/gnu/packages/libunistring.scm?id=de3a1ac64877739d405233e41d720cbf286aa7ec'>gnu: libunistring: Update to 0.9.8.</a><span class='msg-avail'>...</span></td><td>Marius Bakke</td></tr>
<tr><td><span title='2017-11-06 17:32:42 -0600'>2017-11-06</span></td><td><a href='/guix/commit/gnu/packages/libunistring.scm?id=acc2dab7f2f50c9169d6388007c770878eae4a9c'>gnu: Disable gnulib's test-lock test in packages.</a><span class='msg-avail'>...</span></td><td>Eric Bavier</td></tr>
<tr><td><span title='2017-04-17 21:35:38 +0200'>2017-04-17</span></td><td><a href='/guix/commit/gnu/packages/libunistring.scm?id=b100e0e89ebd1a6e73d6be4e354dd684abb057a4'>gnu: libunistring: Fix make check issues on multi-core machines.</a><span class='msg-avail'>...</span></td><td>Mathieu Othacehe</td></tr>
<tr><td><span title='2017-01-06 17:14:41 -0500'>2017-01-06</span></td><td><a href='/guix/commit/gnu/packages/libunistring.scm?id=74288230ea8b2310495dc2739f39ceadcc143fd0'>Merge branch 'master' into core-updates</a></td><td>Leo Famulari</td></tr>
<tr><td><span title='2016-12-07 10:23:17 +0100'>2016-12-07</span></td><td><a href='/guix/commit/gnu/packages/libunistring.scm?id=d788fcd3ba2a780393765013451fcace9bb10800'>gnu: libunistring: support mingw: propagate libiconv if needed.</a><span class='msg-avail'>...</span></td><td>Jan Nieuwenhuizen</td></tr>
<tr><td><span title='2016-12-03 19:35:27 +0200'>2016-12-03</span></td><td><a href='/guix/commit/gnu/packages/libunistring.scm?id=d54c0bfde4fed2160689dc50b659c76cff9724be'>gnu: libunistring: Update to 0.9.7.</a><span class='msg-avail'>...</span></td><td>Efraim Flashner</td></tr>