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='2023-08-21 16:16:47 +0200'>2023-08-21</span></td><td><a href='/guix/commit/tests/graph.scm?id=df2117b8e0e9a35ef8be7f122a783190cafed669'>tests: Adjust 'node-back-edges' test for 'bag' to system-dependent glibc.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2023-04-07 17:53:37 +0200'>2023-04-07</span></td><td><a href='/guix/commit/tests/graph.scm?id=acdb42e5d09a504d521d8b632c2c4a66d70f94e4'>gnu: Purge pre-1.3.0 deprecated packages.</a><span class='msg-avail'>...</span></td><td>Bruno Victal</td></tr>
<tr><td><span title='2022-10-22 01:46:55 +0200'>2022-10-22</span></td><td><a href='/guix/commit/tests/graph.scm?id=a3619079f95213c4f983e69210ed12b38fd31022'>Remove now unnecessary uses of (guix grafts).</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2022-07-01 23:29:16 +0200'>2022-07-01</span></td><td><a href='/guix/commit/tests/graph.scm?id=bee2c369fa2a3d51e6a1218d1b1a0ee86528674a'>tests: Adjust 'guix graph' test to latest OCaml changes.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2022-02-05 08:02:30 +0100'>2022-02-05</span></td><td><a href='/guix/commit/tests/graph.scm?id=45082b9a8c12af285f4386538fc7acc4668cb11c'>tests: Assert that cyclic graphs can be produced.</a><span class='msg-avail'>...</span></td><td>Liliana Marie Prikler</td></tr>