Skip tests that rely on unlinkat(2) behavior that varies between
kernel versions and is unspecified.

See <http://bugs.gnu.org/20597>
and <http://lists.gnu.org/archive/html/bug-tar/2015-06/msg00000.html>.

--- tar-1.28/tests/testsuite	2014-07-27 22:35:27.000000000 +0200
+++ tar-1.28/tests/testsuite	2015-06-16 00:21:16.906380739 +0200
@@ -34680,6 +34680,7 @@ find .
 )"
 at_fn_check_prepare_notrace 'an embedded newline' "remfiles08a.at:31"
 ( $at_check_trace;
+exit 77
 mkdir gnu
 (cd gnu
 TEST_TAR_FORMAT=gnu
@@ -34762,6 +34763,7 @@ find .
 )"
 at_fn_check_prepare_notrace 'an embedded newline' "remfiles08b.at:36"
 ( $at_check_trace;
+exit 77
 mkdir gnu
 (cd gnu
 TEST_TAR_FORMAT=gnu
@@ -34850,6 +34852,7 @@ find .
 )"
 at_fn_check_prepare_notrace 'a `...` command substitution' "remfiles08c.at:31"
 ( $at_check_trace;
+exit 77
 mkdir gnu
 (cd gnu
 TEST_TAR_FORMAT=gnu
r><td class='sub'>Wojtek's customized Guix</td><td class='sub right'></td></tr></table>
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<tr><td><span title='2020-10-23 12:57:20 -0400'>2020-10-23</span></td><td><a href='/guix/commit/HACKING?id=73faee9fb25465f1b236f5f94e1052145655736f'>doc: Fix typo in HACKING.</a><span class='msg-avail'>...<span class='msg-tooltip'>* HACKING (Contributing): s/informations/information/.
</span></span></td><td>Maxim Cournoyer</td></tr>
<tr><td><span title='2020-01-09 23:33:04 +0100'>2020-01-09</span></td><td><a href='/guix/commit/HACKING?id=2d315cd428484537e763d7f7c676dc5fff7995f6'>doc: Move "Commit Access" section from 'HACKING' to the manual.</a><span class='msg-avail'>...<span class='msg-tooltip'>* HACKING (Commit Access): Remove.
(Contributing): Update URL of the manual.
* doc/contributing.texi (Commit Access): New section.
(Submitting Patches): Add cross reference.
</span></span></td><td>Ludovic Courtès</td></tr>
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(Submitting Patches): Refer to it.
* doc/guix.texi: Update copyright line.
* HACKING (Using emacs-debbugs): Remove.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2019-07-13 14:25:19 -0400'>2019-07-13</span></td><td><a href='/guix/commit/HACKING?id=06e1ecbf17fee7fe513ad2808d8175fb3565ae3e'>doc: Update keyserver URL.</a><span class='msg-avail'>...<span class='msg-tooltip'>* HACKING (Commit Access): Change keyserver URL to 'keys.openpgp.org'.
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<tr><td><span title='2019-02-11 23:23:27 +0100'>2019-02-11</span></td><td><a href='/guix/commit/HACKING?id=6701edbfad62ba9572ffd35497df3db27b208ba5'>HACKING: Update key server.</a><span class='msg-avail'>...<span class='msg-tooltip'>* HACKING (Commit Access): Recommend pool.sks-keyservers.net.
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<tr><td><span title='2018-07-22 17:00:47 +0200'>2018-07-22</span></td><td><a href='/guix/commit/HACKING?id=5285192150c83db12136af6a123e03bb9b9dbe5f'>doc: Fix typo (missing period)</a><span class='msg-avail'>...<span class='msg-tooltip'>* HACKING (Commit Access): Fix typo.
</span></span></td><td>Pierre Neidhardt</td></tr>
<tr><td><span title='2017-08-19 13:42:52 +0530'>2017-08-19</span></td><td><a href='/guix/commit/HACKING?id=acabbd597678e1f0be995297bb009b6dd38ae795'>doc: Mention how to use emacs-debbugs.</a><span class='msg-avail'>...<span class='msg-tooltip'>* HACKING (Using emacs-debbugs): Add section on using emacs-debbugs.
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<tr><td><span title='2017-03-27 00:13:18 +0200'>2017-03-27</span></td><td><a href='/guix/commit/HACKING?id=2fccc0d193497eb2ee3127270dea12be103f1bc2'>maint: Give command to install the pre-push hook.</a><span class='msg-avail'>...<span class='msg-tooltip'>* HACKING: Add 'cp' line to install the pre-push hook.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2017-03-24 13:56:38 +0100'>2017-03-24</span></td><td><a href='/guix/commit/HACKING?id=ee7c21c7044355fc4c6bbe0906f061f6fbdfb79e'>maint: Mention the Signed-off-by line in 'HACKING'.</a><span class='msg-avail'>...<span class='msg-tooltip'>* HACKING: Mention the Signed-off-by line.
</span></span></td><td>Clément Lassieur</td></tr>
<tr><td><span title='2017-03-15 15:19:53 +0100'>2017-03-15</span></td><td><a href='/guix/commit/HACKING?id=bc551cf32b6ccb3f8dd60b1d0d4e3c3e88cb1f8d'>maint: Mention guix-patches@gnu.org in 'HACKING'.</a><span class='msg-avail'>...<span class='msg-tooltip'>Fixes &lt;http://bugs.gnu.org/25899&gt;.

* HACKING: Mention guix-patches@gnu.org.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2017-01-30 13:20:13 +0100'>2017-01-30</span></td><td><a href='/guix/commit/HACKING?id=8efc35a8902910ef7c09183c1d79d51498b2c10c'>maint: Fix invalid calls to 'info'.</a><span class='msg-avail'>...<span class='msg-tooltip'>* HACKING &lt;Contributing&gt;: Remove name of the manual from the item argument.
* README &lt;Installation&gt;: Likewise.
</span></span></td><td>Mathieu Lirzin</td></tr>
<tr><td><span title='2017-01-04 16:27:20 -0500'>2017-01-04</span></td><td><a href='/guix/commit/HACKING?id=69355e1283d300a663fb639ec426f10f3feb404b'>doc: Add a Git hook that verifies signatures before pushing.</a><span class='msg-avail'>...<span class='msg-tooltip'>* HACKING (Commit Access): Describe the pre-push Git hook.
* etc/git/pre-push: New file.
</span></span></td><td>Leo Famulari</td></tr>