Don't encode the current timestamp.

This affects the output of `perl -V`, specifically the message "Compiled
at [...]".

The 'cf_time' and 'cf_by' values show up in 'config.h' and
in 'Config_heavy.pl'.

Use the output of 'uname -s' instead of 'uname -a' to avoid recording
the kernel version ('uname -o' leads to directory names like
'x86_64-gnulinux' instead of 'x86_64-linux', which might cause breakage
down the road.)

diff --git a/perl.c b/perl.c
index 228a0d8..ed38313 100644
--- a/perl.c
+++ b/perl.c
@@ -1825,6 +1825,7 @@ S_Internals_V(pTHX_ CV *cv)
     PUSHs(Perl_newSVpvn_flags(aTHX_ non_bincompat_options,
 			      sizeof(non_bincompat_options) - 1, SVs_TEMP));
 
+#define PERL_BUILD_DATE "Jan  1 1970 00:00:00"
 #ifndef PERL_BUILD_DATE
 #  ifdef __DATE__
 #    ifdef __TIME__

--- a/Configure	1970-01-01 01:00:00.000000000 +0100
+++ b/Configure	2016-10-01 14:47:20.017319739 +0200
@@ -3276,7 +3276,7 @@ $eunicefix tr
 : Try to determine whether config.sh was made on this system
 case "$config_sh" in
 '')
-myuname=`$uname -a 2>/dev/null`
+myuname=`$uname -s 2>/dev/null`
 $test -z "$myuname" && myuname=`hostname 2>/dev/null`
 # Downcase everything to avoid ambiguity.
 # Remove slashes and single quotes so we can use parts of this in
@@ -3845,10 +3845,10 @@
 . ./posthint.sh
 
 : who configured the system
-cf_time=`LC_ALL=C; LANGUAGE=C; export LC_ALL; export LANGUAGE; $date 2>&1`
+cf_time="1970-01-01"
 case "$cf_by" in
 "")
-	cf_by=`(logname) 2>/dev/null`
+	cf_by="guix"
 	case "$cf_by" in
 	"")
 		cf_by=`(whoami) 2>/dev/null`
e='hidden' name='id' value='126a91888c921179e90090c4c023d6285bfd44a0'/><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=126a91888c921179e90090c4c023d6285bfd44a0'>root</a>/<a href='/guix/log/gnu?id=126a91888c921179e90090c4c023d6285bfd44a0'>gnu</a>/<a href='/guix/log/gnu/tests.scm?id=126a91888c921179e90090c4c023d6285bfd44a0'>tests.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/tests.scm?id=126a91888c921179e90090c4c023d6285bfd44a0&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2023-04-21 16:16:38 +0200'>2023-04-21</span></td><td><a href='/guix/commit/gnu/tests.scm?id=a09c7da8f8d8e732f969cf0a09aaa78f87032ab1'>tests: Fork and exec a new Guile for the marionette REPL.</a><span class='msg-avail'>...<span class='msg-tooltip'>By merely forking PID 1, details from PID 1 (shepherd) would leak into
the marionette process, such as the set of modules in scope and state
inherited from the shepherd process (&lt;service&gt; instances, fibers,
etc.).  Running a fresh Guile instance avoids that.

* gnu/tests.scm (marionette-program): New procedure.
(marionette-shepherd-service): Change 'start' to use
'make-forkexec-constructor', and run the result of 'marionette-program'.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2022-05-18 22:29:54 +0200'>2022-05-18</span></td><td><a href='/guix/commit/gnu/tests.scm?id=9a5d68692314bebd16dbcdc0d4e4e52fa4d5812f'>services: Add more description fields.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/services.scm (simple-service): Add 'description' field.
* gnu/services/base.scm (udev-rules-service): Likewise.
* gnu/system/install.scm (configuration-template-service-type): Likewise.
* gnu/tests.scm (marionette-service-type): Likewise.
</span></span></td><td>Ludovic Courtès</td></tr>