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
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<tr><td><span title='2019-03-24 23:06:12 +0100'>2019-03-24</span></td><td><a href='/guix/commit/gnu/system?id=ae7a316b9da0d1a50c5abdc531c68c8e98e561c9'>system: Initialize console keyboard layout in the initrd.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2019-03-24 23:06:11 +0100'>2019-03-24</span></td><td><a href='/guix/commit/gnu/system?id=132823c2acd34f46d6df89ce3635db62643a09c8'>vm: 'virtualized-operating-system' inherits from the user's bootloader config.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2019-03-24 23:06:11 +0100'>2019-03-24</span></td><td><a href='/guix/commit/gnu/system?id=db1e2522f6222594fc507ce7a7ba7b1c0ac5037d'>Add (gnu system keyboard).</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2019-03-22 22:49:35 +0100'>2019-03-22</span></td><td><a href='/guix/commit/gnu/system?id=0dc7d298a33f83d5f02a962b5f1bd24ee0e8ef07'>vm: 'system-docker-image' calls 'sync' before rebooting.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2019-03-17 16:30:00 +0100'>2019-03-17</span></td><td><a href='/guix/commit/gnu/system?id=e6c46ec42ea6e986b1030a145cb391235b689735'>vm: 'expression-&gt;derivation-in-linux-vm' leads to a kernel panic upon failure.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2019-03-13 23:12:44 +0100'>2019-03-13</span></td><td><a href='/guix/commit/gnu/system?id=b94c80ff5d844f7763738ab5359fee72f11f9367'>linux-container: 'containerized-operating-system' removes "useless" services.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2019-03-13 23:12:43 +0100'>2019-03-13</span></td><td><a href='/guix/commit/gnu/system?id=4cd386afae444f3ee603cd07d282b2eee3253555'>linux-modules: Factorize 'missing-modules'.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2019-03-13 23:12:43 +0100'>2019-03-13</span></td><td><a href='/guix/commit/gnu/system?id=59e80445882f8b0379e54916f89510c0deda6698'>Remove traces of "GuixSD".</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>