The Clar test framework has a bug whereby it skips the parsing phase
on files with mtime=0.

Reported upstream at <https://github.com/vmg/clar/pull/78>.

diff --git a/tests/generate.py b/tests/generate.py
index b639c8f..111ca41 100644
--- a/tests/generate.py
+++ b/tests/generate.py
@@ -63,3 +63,3 @@ class Module(object):
 
-        self.mtime = 0
+        self.mtime = None # Guix sets all file mtimes to '0'
         self.enabled = True
/cgit-static/cgit.png' alt='cgit logo'/></a></td>
<td class='main'><a href='/'>index</a> : <a href='/guix/'>guix</a></td><td class='form'><form method='get'>
<input type='hidden' name='id' value='e6b2552a96b328d81f681c2ae17c54a795ab2547'/><select name='h' onchange='this.form.submit();'>
<option value='koszko' selected='selected'>koszko</option>
<option value='koszko-scripts'>koszko-scripts</option>
</select> <input type='submit' value='switch'/></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=e6b2552a96b328d81f681c2ae17c54a795ab2547'>refs</a><a class='active' href='/guix/log/gnu/services/audio.scm'>log</a><a href='/guix/tree/gnu/services/audio.scm?id=e6b2552a96b328d81f681c2ae17c54a795ab2547'>tree</a><a href='/guix/commit/gnu/services/audio.scm?id=e6b2552a96b328d81f681c2ae17c54a795ab2547'>commit</a><a href='/guix/diff/gnu/services/audio.scm?id=e6b2552a96b328d81f681c2ae17c54a795ab2547'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/gnu/services/audio.scm'>
<input type='hidden' name='id' value='e6b2552a96b328d81f681c2ae17c54a795ab2547'/><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=e6b2552a96b328d81f681c2ae17c54a795ab2547'>root</a>/<a href='/guix/log/gnu?id=e6b2552a96b328d81f681c2ae17c54a795ab2547'>gnu</a>/<a href='/guix/log/gnu/services?id=e6b2552a96b328d81f681c2ae17c54a795ab2547'>services</a>/<a href='/guix/log/gnu/services/audio.scm?id=e6b2552a96b328d81f681c2ae17c54a795ab2547'>audio.scm</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/gnu/services/audio.scm?id=e6b2552a96b328d81f681c2ae17c54a795ab2547&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2020-05-13 23:35:57 +0200'>2020-05-13</span></td><td><a href='/guix/commit/gnu/services/audio.scm?id=ad263045b9bf016d6f4fbb1f7fde0f51d3194944'>services: Add missing import.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2019-11-08 21:32:45 +0100'>2019-11-08</span></td><td><a href='/guix/commit/gnu/services/audio.scm?id=970cb5ceceaa85765230a9f896a43783cdcb4e6c'>services: mpd: Connect to the user's PulseAudio socket.</a><span class='msg-avail'>...</span></td><td>Robert Smith</td></tr>
<tr><td><span title='2019-10-29 15:14:22 +0100'>2019-10-29</span></td><td><a href='/guix/commit/gnu/services/audio.scm?id=878e0e1bb0d15809c6582436d53498f3e6385524'>gnu: mpd-service-type: Support configuration of outputs.</a><span class='msg-avail'>...</span></td><td>Ricardo Wurmus</td></tr>
<tr><td><span title='2019-03-15 23:27:59 +0100'>2019-03-15</span></td><td><a href='/guix/commit/gnu/services/audio.scm?id=c71b7b5b3740177f0df6d3565dcc356ceda1acba'>services: mpd: add more configuration options</a><span class='msg-avail'>...</span></td><td>nixo</td></tr>
<tr><td><span title='2017-11-05 15:29:52 +0100'>2017-11-05</span></td><td><a href='/guix/commit/gnu/services/audio.scm?id=21b71b01e9c2264c31ef30451c152bb38cc9e635'>services: Add 'description' fields.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2017-08-31 14:43:26 +0200'>2017-08-31</span></td><td><a href='/guix/commit/gnu/services/audio.scm?id=b6dc69af1de806e8b3a70e9a1afe0e1590da5480'>services: mpd: Remove the mpd-file field.</a><span class='msg-avail'>...</span></td><td>Peter Mikkelsen</td></tr>
<tr><td><span title='2017-08-13 07:36:32 +0100'>2017-08-13</span></td><td><a href='/guix/commit/gnu/services/audio.scm?id=06465d2ba4291eb2046c90c3977a295a9b7c434b'>gnu: Add mpd service.</a><span class='msg-avail'>...</span></td><td>Peter Mikkelsen</td></tr>