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
itch'/></form></td></tr>
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<tr><td><span title='2022-09-28 09:06:10 +0200'>2022-09-28</span></td><td><a href='/guix/commit/NEWS?id=70a593242e6b288a0348154f09c4ddbc732463d8'>Update NEWS.</a><span class='msg-avail'>...</span></td><td>Mathieu Othacehe</td></tr>
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<tr><td><span title='2021-06-29 14:53:21 -0400'>2021-06-29</span></td><td><a href='/guix/commit/NEWS?id=82daab42811a2e3c7684ebdf12af75ff0fa67b99'>pack: Add support for the deb format.</a><span class='msg-avail'>...</span></td><td>Maxim Cournoyer</td></tr>
<tr><td><span title='2021-05-10 13:48:30 -0400'>2021-05-10</span></td><td><a href='/guix/commit/NEWS?id=80dc6ad4a89b68b5e837fc22c9b1322b86527bef'>Update NEWS.</a></td><td>Maxim Cournoyer</td></tr>
<tr><td><span title='2021-05-10 11:21:02 -0400'>2021-05-10</span></td><td><a href='/guix/commit/NEWS?id=7418a200742768d21b567916b25e4d3351472230'>Update NEWS.</a></td><td>Leo Famulari</td></tr>
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