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=806a4e986d95a31cf09588cf10d1b9dae28a3d5e'>root</a>/<a href='/guix/log/gnu?id=806a4e986d95a31cf09588cf10d1b9dae28a3d5e'>gnu</a>/<a href='/guix/log/gnu/build?id=806a4e986d95a31cf09588cf10d1b9dae28a3d5e'>build</a>/<a href='/guix/log/gnu/build/bootloader.scm?id=806a4e986d95a31cf09588cf10d1b9dae28a3d5e'>bootloader.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/build/bootloader.scm?id=806a4e986d95a31cf09588cf10d1b9dae28a3d5e&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2021-11-12 13:26:52 +0000'>2021-11-12</span></td><td><a href='/guix/commit/gnu/build/bootloader.scm?id=fb3df2011692b2a6fea9f4fefd71dd788453fbae'>build: bootloader: Add GPT support.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/build/bootloader.scm (install-efi-loader): Add GPT support.
</span></span></td><td>Mathieu Othacehe</td></tr>
<tr><td><span title='2020-11-03 07:59:59 +0100'>2020-11-03</span></td><td><a href='/guix/commit/gnu/build/bootloader.scm?id=a38d861e571c952f78ca588b50bdcc4adcb0c88c'>system: reconfigure: Use the disk-installer if provided.</a><span class='msg-avail'>...<span class='msg-tooltip'>Fixes: &lt;https://issues.guix.gnu.org/44101&gt;.

* gnu/build/bootloader.scm (write-file-on-device): Pass 'no-fail flag instead
of 'no-create. Use a latin-1 transcoder.
* guix/scripts/system/reconfigure.scm (install-bootloader-program): Add a
"disk-installer" argument and use it as a fallback.
(install-bootloader): Adapt accordingly.
* gnu/tests/reconfigure.scm (run-install-bootloader-test): Ditto.
</span></span></td><td>Mathieu Othacehe</td></tr>
<tr><td><span title='2020-10-05 11:10:35 +0200'>2020-10-05</span></td><td><a href='/guix/commit/gnu/build/bootloader.scm?id=b97b423e3f61c80d5877dadc95b3f316cd61788f'>bootloader: Fix u-boot installation.</a><span class='msg-avail'>...<span class='msg-tooltip'>This is a follow-up of f19cf27c2b9ff92e2c0fd931ef7fde39c376adaa. The
bootloader installation must be done on the final disk-image, hence using
"disk-image-installer" instead of "installer" callback.

* gnu/bootloader/u-boot.scm: Turn all installer callbacks into
disk-image-installer callbacks.
* gnu/build/bootloader.scm (write-file-on-device): Open the output file with
'no-truncate and 'no-create options.
* gnu/system/image.scm (with-imported-modules*): Add (gnu build bootloader)
module.
</span></span></td><td>Mathieu Othacehe</td></tr>
<tr><td><span title='2020-05-05 16:08:33 +0200'>2020-05-05</span></td><td><a href='/guix/commit/gnu/build/bootloader.scm?id=f8fd1157174fd523d36dcfa756c965a54c30d5ae'>build: bootloader: Add install-efi procedure.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/build/bootloader.scm (install-efi): New procedure copied from (gnu build vm).
(install-efi-loader): New exported procedure, wrapping install-efi.
* gnu/build/vm.scm (initialize-hard-disk): Adapt to use install-efi-loader.
</span></span></td><td>Mathieu Othacehe</td></tr>