Fix CVE-2018-1000097:

https://security-tracker.debian.org/tracker/CVE-2018-1000097
https://nvd.nist.gov/vuln/detail/CVE-2018-1000097

Patch taken from upstream bug report:
https://lists.gnu.org/archive/html/bug-gnu-utils/2018-02/msg00005.html

diff --git a/src/unshar.c b/src/unshar.c
index 80bc3a9..0fc3773 100644
--- a/src/unshar.c
+++ b/src/unshar.c
@@ -240,7 +240,7 @@ find_archive (char const * name, FILE * file, off_t start)
       off_t position = ftello (file);
 
       /* Read next line, fail if no more and no previous process.  */
-      if (!fgets (rw_buffer, BUFSIZ, file))
+      if (!fgets (rw_buffer, rw_base_size, file))
 	{
 	  if (!start)
 	    error (0, 0, _("Found no shell commands in %s"), name);
);'>
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<tr><td><span title='2020-05-13 09:30:26 +0300'>2020-05-13</span></td><td><a href='/guix/commit/gnu/packages/autotools.scm?id=3c986a7dc268756c097212de958f046b29b76c1b'>mailmap: Update entries for Nikita.</a><span class='msg-avail'>...</span></td><td>nikita</td></tr>
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<tr><td><span title='2020-03-27 00:21:10 +0100'>2020-03-27</span></td><td><a href='/guix/commit/gnu/packages/autotools.scm?id=20586ffdc746b17f8208e77852752e99bf5bee55'>gnu: Automake: Remove version 1.16.1.</a><span class='msg-avail'>...</span></td><td>Marius Bakke</td></tr>
<tr><td><span title='2020-03-27 00:12:15 +0100'>2020-03-27</span></td><td><a href='/guix/commit/gnu/packages/autotools.scm?id=18af6870370226b4d502d7372844e7f2aded5887'>Merge branch 'master' into core-updates</a><span class='msg-avail'>...</span></td><td>Marius Bakke</td></tr>
<tr><td><span title='2020-03-24 18:03:18 +0100'>2020-03-24</span></td><td><a href='/guix/commit/gnu/packages/autotools.scm?id=72a5cc53586080e75ae4ee80f3a2467ff30c4f5e'>gnu: automake: Add version 1.16.2.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2020-03-14 13:13:40 +0100'>2020-03-14</span></td><td><a href='/guix/commit/gnu/packages/autotools.scm?id=961d2ee2695b38503b463d055e9c7edbcc0bf307'>Merge branch 'master' into core-updates</a></td><td>Marius Bakke</td></tr>
<tr><td><span title='2020-03-13 05:36:09 +0100'>2020-03-13</span></td><td><a href='/guix/commit/gnu/packages/autotools.scm?id=2eed6813b6a447524fad8c29412a1efc8c135456'>gnu: autobuild: Use HTTPS home page.</a><span class='msg-avail'>...</span></td><td>Tobias Geerinckx-Rice</td></tr>
<tr><td><span title='2020-03-04 23:16:17 +0100'>2020-03-04</span></td><td><a href='/guix/commit/gnu/packages/autotools.scm?id=ebb7cf9e21060105d9950dd5142c0eb918083666'>Merge branch 'master' into core-updates</a></td><td>Marius Bakke</td></tr>
<tr><td><span title='2020-02-16 22:54:47 +0100'>2020-02-16</span></td><td><a href='/guix/commit/gnu/packages/autotools.scm?id=25ee4a474511162e3ad98e7ecb0d06cedf438b0f'>gnu: autoconf: Use HTTPS home page.</a><span class='msg-avail'>...</span></td><td>Tobias Geerinckx-Rice</td></tr>