Always provide the same date and time in 'Py_GetBuildInfo'.
This is the information shown at the REPL and in 'sys.version'.
We cannot pass it in CPPFLAGS due to whitespace in the DATE string.

--- a/Modules/getbuildinfo.c
+++ b/Modules/getbuildinfo.c
@@ -4,6 +4,10 @@
 #include <stdio.h>
 #endif
 
+/* Deterministic date and time.  */
+#define DATE "Jan  1 1970"
+#define TIME "00:00:01"
+
 #ifndef DATE
 #ifdef __DATE__
 #define DATE __DATE__
ogo'/></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='a91c3d336cb42c195350cb61c74f8e9b5a02bfc2'/><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=a91c3d336cb42c195350cb61c74f8e9b5a02bfc2'>refs</a><a class='active' href='/guix/log/gnu/system/pam.scm'>log</a><a href='/guix/tree/gnu/system/pam.scm?id=a91c3d336cb42c195350cb61c74f8e9b5a02bfc2'>tree</a><a href='/guix/commit/gnu/system/pam.scm?id=a91c3d336cb42c195350cb61c74f8e9b5a02bfc2'>commit</a><a href='/guix/diff/gnu/system/pam.scm?id=a91c3d336cb42c195350cb61c74f8e9b5a02bfc2'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/gnu/system/pam.scm'>
<input type='hidden' name='id' value='a91c3d336cb42c195350cb61c74f8e9b5a02bfc2'/><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=a91c3d336cb42c195350cb61c74f8e9b5a02bfc2'>root</a>/<a href='/guix/log/gnu?id=a91c3d336cb42c195350cb61c74f8e9b5a02bfc2'>gnu</a>/<a href='/guix/log/gnu/system?id=a91c3d336cb42c195350cb61c74f8e9b5a02bfc2'>system</a>/<a href='/guix/log/gnu/system/pam.scm?id=a91c3d336cb42c195350cb61c74f8e9b5a02bfc2'>pam.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/system/pam.scm?id=a91c3d336cb42c195350cb61c74f8e9b5a02bfc2&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2021-08-17 01:10:25 +0300'>2021-08-17</span></td><td><a href='/guix/commit/gnu/system/pam.scm?id=b948ab8b56ac238e7a774625b8f971d28aee6055'>services: slim: Add pam-gnupg support.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/system/pam.scm (unix-pam-service): Add account and session PAM entries
for pam-gnupg.  Don't pass "#f" to "allow-root?" argument, because "lambda*"
already does this by default.
* doc/guix.texi (X Window): Document this.
* gnu/services/xorg.scm (&lt;slim-configuration&gt;)[gnupg?]: New record field.
(slim-pam-service): Pass "#:gnupg?" argument to "unix-pam-service".
</span></span></td><td>Oleg Pykhalov</td></tr>
<tr><td><span title='2020-05-08 16:30:50 +0200'>2020-05-08</span></td><td><a href='/guix/commit/gnu/system/pam.scm?id=dd0804c67e99914eecc471fdb92f4220425a1cbc'>services: Add descriptions.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/services/dbus.scm (polkit-service-type)[description]: New field.
* gnu/services/dict.scm (dicod-service-type)[description]: New field.
* gnu/services/dns.scm (knot-service-type)[description]: New field.
* gnu/services/networking.scm (dhcpd-service-type)[description]: New field.
* gnu/services/shepherd.scm (shepherd-root-service-type)[description]:
New field.
* gnu/services/xorg.scm (slim-service-type)[description]: New field.
(screen-locker-service-type)[description]: New field.
* gnu/system/pam.scm (pam-root-service-type)[description]: New field.
* gnu/system/shadow.scm (account-service-type)[description]: New field.
</span></span></td><td>Ludovic Courtès</td></tr>