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
form></td></tr>
<tr><td class='sub'>Wojtek's customized Guix</td><td class='sub right'></td></tr></table>
<table class='tabs'><tr><td>
<a href='/guix/about/'>about</a><a href='/guix/'>summary</a><a href='/guix/refs/?id=a83d31ef844ada117e21e803cadcacc8e9d6358e'>refs</a><a class='active' href='/guix/log/config-daemon.ac'>log</a><a href='/guix/tree/config-daemon.ac?id=a83d31ef844ada117e21e803cadcacc8e9d6358e'>tree</a><a href='/guix/commit/config-daemon.ac?id=a83d31ef844ada117e21e803cadcacc8e9d6358e'>commit</a><a href='/guix/diff/config-daemon.ac?id=a83d31ef844ada117e21e803cadcacc8e9d6358e'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/config-daemon.ac'>
<input type='hidden' name='id' value='a83d31ef844ada117e21e803cadcacc8e9d6358e'/><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=a83d31ef844ada117e21e803cadcacc8e9d6358e'>root</a>/<a href='/guix/log/config-daemon.ac?id=a83d31ef844ada117e21e803cadcacc8e9d6358e'>config-daemon.ac</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/config-daemon.ac?id=a83d31ef844ada117e21e803cadcacc8e9d6358e&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2019-11-27 00:03:03 +0100'>2019-11-27</span></td><td><a href='/guix/commit/config-daemon.ac?id=7738a72186583afb3bb2e0a866c8aba130372400'>daemon: GC remove-unused-links phase uses 'statx' when available.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2019-11-13 23:26:35 +0100'>2019-11-13</span></td><td><a href='/guix/commit/config-daemon.ac?id=298fb2907e3f432cea7dee9f58e89ab8d9dbd56f'>daemon: Don't include &lt;linux/fs.h&gt;.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2019-09-08 11:49:24 +0200'>2019-09-08</span></td><td><a href='/guix/commit/config-daemon.ac?id=f6919ebdc6b0ce0286814cc6ab0564b1a4c67f5f'>daemon: Run 'guix substitute' directly and assume a single substituter.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2019-09-08 11:49:24 +0200'>2019-09-08</span></td><td><a href='/guix/commit/config-daemon.ac?id=bc69ea2d605810cc32e13ed03d5848b8dc358b61'>daemon: Run 'guix offload' directly.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2019-09-08 11:49:24 +0200'>2019-09-08</span></td><td><a href='/guix/commit/config-daemon.ac?id=9fcc35c51fd579b3bb7b4f61cba6973675c3922c'>daemon: Run 'guix perform-download' directly.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2019-09-08 11:49:24 +0200'>2019-09-08</span></td><td><a href='/guix/commit/config-daemon.ac?id=0c684b7edfacada4f576855dbb09291f04a84fa2'>daemon: Run 'guix authenticate' directly.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2019-09-08 11:49:24 +0200'>2019-09-08</span></td><td><a href='/guix/commit/config-daemon.ac?id=2e3e5d21988fc2cafb2a9eaf4b00976ea425629d'>daemon: Invoke 'guix gc --list-busy' instead of 'list-runtime-roots'.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2019-05-01 11:05:47 +0200'>2019-05-01</span></td><td><a href='/guix/commit/config-daemon.ac?id=757e633d57a7b994759d69e41dd759a39f1a34ae'>build: Change default substitute server to "ci.guix.gnu.org".</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2018-12-04 10:57:56 +0100'>2018-12-04</span></td><td><a href='/guix/commit/config-daemon.ac?id=0a5fa004f7f21dc3e01747b8e94fbb21e056e4ca'>build: Default to https://ci.guix.info for substitutes.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2018-11-14 21:34:08 +0100'>2018-11-14</span></td><td><a href='/guix/commit/config-daemon.ac?id=0fe1fba4af41f267c4bb2c006fb37f42422ab703'>daemon: Install 'authenticate' script under LIBEXECDIR/guix.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>