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__
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<tr><td><span title='2022-06-16 23:57:40 +0200'>2022-06-16</span></td><td><a href='/guix/commit/tests/guix-shell-export-manifest.sh?id=925a57c5d04553ff6c514867348e7d3c5c22ca66'>shell: Fix '--export-manifest' for cached profiles and when '-p' is used.</a><span class='msg-avail'>...<span class='msg-tooltip'>Fixes &lt;https://issues.guix.gnu.org/55521&gt;.

* guix/scripts/shell.scm (export-manifest): When computing 'manifest',
honor the 'profile key.
* tests/guix-shell-export-manifest.sh: Add test.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2022-06-01 22:22:19 +0200'>2022-06-01</span></td><td><a href='/guix/commit/tests/guix-shell-export-manifest.sh?id=2acc83daa5a3dd1b4ed3f8c32ecadf1313e6fd18'>shell: '--export-manifest -D x -D y' generates a valid manifest.</a><span class='msg-avail'>...<span class='msg-tooltip'>* guix/scripts/shell.scm (manifest-&gt;code*): Add missing 'list' in
generated 'concatenate-manifests' call.
* tests/guix-shell-export-manifest.sh: Add test.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2022-04-08 18:14:35 +0200'>2022-04-08</span></td><td><a href='/guix/commit/tests/guix-shell-export-manifest.sh?id=20691c70cf2c5a61af7f906b65d57a524ecfc4f3'>tests: 'guix shell --export-manifest' test no longer needs networking.</a><span class='msg-avail'>...<span class='msg-tooltip'>* tests/guix-shell-export-manifest.sh: Use '--with-input' rather than
'--with-latest' as the latter would crash in the absence of network
access.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2022-04-04 22:58:04 +0200'>2022-04-04</span></td><td><a href='/guix/commit/tests/guix-shell-export-manifest.sh?id=c42b7baf13c7633b4512e94da7445299c57b247d'>shell: Add '--export-manifest'.</a><span class='msg-avail'>...<span class='msg-tooltip'>* guix/scripts/shell.scm (show-help, %options): Add '--export-manifest'.
(manifest-entry-version-prefix, manifest-&gt;code*)
(export-manifest): New procedures.
(guix-shell): Honor '--export-manifest'.
* tests/guix-shell-export-manifest.sh: New file.
* Makefile.am (SH_TESTS): Add it.
* doc/guix.texi (Invoking guix shell): Document '--export-manifest'.
(Invoking guix environment): Link to it.
(Invoking guix pack): Likewise.
</span></span></td><td>Ludovic Courtès</td></tr>