The Guile process taking the role of PID 1 during Guix builds does not reap
zombie processes, which makes them continue responding to "kill -0".

--- a/src/testsuite/stop-server.sh	2015-02-05 11:24:00.535908842 +0100
+++ b/src/testsuite/stop-server.sh	2015-02-05 11:25:00.264351349 +0100
@@ -1,6 +1,21 @@
 #!/bin/sh
 # ngIRCd Test Suite
 
+process_is_alive(){
+    ! process_is_dead "$1" && ! process_is_undead "$1"
+}
+
+process_is_dead(){
+    ! kill -0 "$1"
+}
+
+process_is_undead(){
+    case $(ps -p "$1" -o state=) in
+        (Z*) true ;;
+        (*) false ;;
+    esac
+}
+
 [ -z "$srcdir" ] && srcdir=`dirname $0`
 
 # read in functions
@@ -24,7 +40,7 @@
 
 # waiting ...
 for i in 1 2 3 4 5; do
-  kill -0 $pid > /dev/null 2>&1; r=$?
+  process_is_alive $pid > /dev/null 2>&1; r=$?
   if [ $r -ne 0 ]; then
     echo " ok".
     exit 0
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<div class='path'>path: <a href='/guix/log/?id=ad871fd17ff4223d1137239d06fad63244e1847a'>root</a>/<a href='/guix/log/gnu?id=ad871fd17ff4223d1137239d06fad63244e1847a'>gnu</a>/<a href='/guix/log/gnu/tests?id=ad871fd17ff4223d1137239d06fad63244e1847a'>tests</a>/<a href='/guix/log/gnu/tests/monitoring.scm?id=ad871fd17ff4223d1137239d06fad63244e1847a'>monitoring.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/monitoring.scm?id=ad871fd17ff4223d1137239d06fad63244e1847a&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2023-05-06 17:12:45 +0200'>2023-05-06</span></td><td><a href='/guix/commit/gnu/tests/monitoring.scm?id=f51888272558d98cf5c196b93fb6c499056fbf6c'>tests: Add missing module imports for marionette-evaluated code.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2021-09-26 23:20:56 +0200'>2021-09-26</span></td><td><a href='/guix/commit/gnu/tests/monitoring.scm?id=89b05442933d92f4b21c3294455a498e8333727d'>tests: Reduce boilerplate for users of 'system-test-runner'.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2021-09-25 18:52:05 +0200'>2021-09-25</span></td><td><a href='/guix/commit/gnu/tests/monitoring.scm?id=1fb75128a5202b406622da6272bc809c46d1f439'>tests: Adjust to SRFI-64 as found in Guile 3.0.7.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2021-04-12 19:12:46 -0400'>2021-04-12</span></td><td><a href='/guix/commit/gnu/tests/monitoring.scm?id=c311147bd16aa0e5746d9cbf31502f5fd61e470c'>services: postgresql: Change service default socket directory.</a><span class='msg-avail'>...</span></td><td>Christopher Baines</td></tr>
<tr><td><span title='2021-02-01 14:18:38 -0500'>2021-02-01</span></td><td><a href='/guix/commit/gnu/tests/monitoring.scm?id=75b775e81b5a81a59656eeba8811b42f45d503da'>Merge branch 'staging'</a></td><td>Leo Famulari</td></tr>
<tr><td><span title='2021-01-28 12:57:26 +0100'>2021-01-28</span></td><td><a href='/guix/commit/gnu/tests/monitoring.scm?id=6c0679215f4ffa534c1eb2e8c8a6e043a0c993fe'>services: postgresql: Add socket directory support.</a><span class='msg-avail'>...</span></td><td>Mathieu Othacehe</td></tr>
<tr><td><span title='2021-01-04 18:07:53 -0500'>2021-01-04</span></td><td><a href='/guix/commit/gnu/tests/monitoring.scm?id=48d8d92c51f64256bba2bdbb2a1027a5fab71a3d'>tests: monitoring: Use the latest postgresql for testing Zabbix.</a><span class='msg-avail'>...</span></td><td>Leo Famulari</td></tr>
<tr><td><span title='2020-10-20 22:39:43 +0100'>2020-10-20</span></td><td><a href='/guix/commit/gnu/tests/monitoring.scm?id=bdcf4d88d58798eca7811c8b1fbd4638168d05c3'>services: databases: Don't specify a default postgresql version.</a><span class='msg-avail'>...</span></td><td>Christopher Baines</td></tr>
<tr><td><span title='2020-10-20 22:39:42 +0100'>2020-10-20</span></td><td><a href='/guix/commit/gnu/tests/monitoring.scm?id=dd2e6e31edff2d83c8820bb10e588c06495dc122'>tests: monitoring: Use (service postgresql-service-type).</a><span class='msg-avail'>...</span></td><td>Christopher Baines</td></tr>
<tr><td><span title='2020-07-15 22:15:50 +0300'>2020-07-15</span></td><td><a href='/guix/commit/gnu/tests/monitoring.scm?id=37fea3c30a79d2c401dd64b446a0fbfe4a14b966'>tests: zabbix: Fix typo in comment.</a><span class='msg-avail'>...</span></td><td>Oleg Pykhalov</td></tr>