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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<tr><td><span title='2019-12-25 17:10:51 +0100'>2019-12-25</span></td><td><a href='/guix/commit/gnu/packages/lxde.scm?id=450cd92f21d967d92fc76047f8c09ccf51bbd0e0'>gnu: lxtask: Don't use NAME in source URI.</a><span class='msg-avail'>...</span></td><td>Tobias Geerinckx-Rice</td></tr>
<tr><td><span title='2019-12-25 17:10:51 +0100'>2019-12-25</span></td><td><a href='/guix/commit/gnu/packages/lxde.scm?id=fd71c6f43ba5bf8e11d82854cfe4b1d0a02f948d'>gnu: lxtask: Update to 0.1.9.</a><span class='msg-avail'>...</span></td><td>Tobias Geerinckx-Rice</td></tr>