Unconditionally enable PGRP_PIPE on Linux (the kernel), regardless of
the kernel version in use on the build machine.

--- configure.ac.orig	2019-01-02 09:38:44.000000000 -0500
+++ configure.ac	2019-08-15 16:40:24.271758379 -0400
@@ -1108,10 +1108,7 @@
 solaris2*)	LOCAL_CFLAGS=-DSOLARIS ;;
 lynxos*)	LOCAL_CFLAGS=-DRECYCLES_PIDS ;;
 linux*)		LOCAL_LDFLAGS=-rdynamic		 # allow dynamic loading
-		case "`uname -r`" in
-		1.*|2.[[0123]]*)	: ;;
-		*)	AC_DEFINE(PGRP_PIPE) ;;
-		esac ;;
+		AC_DEFINE(PGRP_PIPE) ;;
 netbsd*|openbsd*)	LOCAL_CFLAGS="-DDEV_FD_STAT_BROKEN" ;;
 *qnx[[67]]*)	LOCAL_LIBS="-lncurses" ;;
 *qnx*)		LOCAL_CFLAGS="-Dqnx -F -3s" LOCAL_LDFLAGS="-3s" LOCAL_LIBS="-lunix -lncurses" ;;
--- configure.orig	2019-01-02 09:43:04.000000000 -0500
+++ configure	2019-08-15 16:41:44.440155912 -0400
@@ -16312,11 +16312,7 @@
 solaris2*)	LOCAL_CFLAGS=-DSOLARIS ;;
 lynxos*)	LOCAL_CFLAGS=-DRECYCLES_PIDS ;;
 linux*)		LOCAL_LDFLAGS=-rdynamic		 # allow dynamic loading
-		case "`uname -r`" in
-		1.*|2.[0123]*)	: ;;
-		*)	$as_echo "#define PGRP_PIPE 1" >>confdefs.h
- ;;
-		esac ;;
+		$as_echo "#define PGRP_PIPE 1" >>confdefs.h ;;
 netbsd*|openbsd*)	LOCAL_CFLAGS="-DDEV_FD_STAT_BROKEN" ;;
 *qnx[67]*)	LOCAL_LIBS="-lncurses" ;;
 *qnx*)		LOCAL_CFLAGS="-Dqnx -F -3s" LOCAL_LDFLAGS="-3s" LOCAL_LIBS="-lunix -lncurses" ;;
x/commit/tests/records.scm?id=e863cf42036cd8d06e96fe29068eb0309e895e43'>commit</a><a href='/guix/diff/tests/records.scm?id=e863cf42036cd8d06e96fe29068eb0309e895e43'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/tests/records.scm'>
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<div class='path'>path: <a href='/guix/log/?id=e863cf42036cd8d06e96fe29068eb0309e895e43'>root</a>/<a href='/guix/log/tests?id=e863cf42036cd8d06e96fe29068eb0309e895e43'>tests</a>/<a href='/guix/log/tests/records.scm?id=e863cf42036cd8d06e96fe29068eb0309e895e43'>records.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/tests/records.scm?id=e863cf42036cd8d06e96fe29068eb0309e895e43&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2022-12-02 00:02:12 +0100'>2022-12-02</span></td><td><a href='/guix/commit/tests/records.scm?id=7c1161dba4c8930d3a500a72ccaaaf50df73f466'>records: 'match-record' checks fields at macro-expansion time.</a><span class='msg-avail'>...<span class='msg-tooltip'>This allows 'match-record' to be more efficient (field offsets are
computed at compilation time) and to report unknown fields at
macro-expansion time.

* guix/records.scm (map-fields): New macro.
(define-record-type*)[rtd-identifier]: New procedure.
Define TYPE as a macro and use a separate identifier for the RTD.
(lookup-field, match-record-inner): New macros.
(match-record): Rewrite in terms of 'match-error-inner'.
* tests/records.scm ("match-record, simple")
("match-record, unknown field"): New tests.
* gnu/services/cuirass.scm (cuirass-shepherd-service): Rename 'log-file'
local variable to 'main-log-file'.
* gnu/services/getmail.scm (serialize-getmail-configuration-file): Move
after &lt;getmail-configuration-file&gt; definition.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2022-07-01 12:10:29 +0200'>2022-07-01</span></td><td><a href='/guix/commit/tests/records.scm?id=741895676b124a8a9a6656a54b5b58fd35d8e0f9'>tests: Add sanitizer test.</a><span class='msg-avail'>...<span class='msg-tooltip'>* tests/records.scm ("define-record-type* &amp; sanitize without default
value"): New test.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2021-08-12 12:34:13 +0200'>2021-08-12</span></td><td><a href='/guix/commit/tests/records.scm?id=5291fd7a4205394b863a8705b32fbb447321dc60'>records: Support field sanitizers.</a><span class='msg-avail'>...<span class='msg-tooltip'>* guix/records.scm (make-syntactic-constructor): Add #:sanitizers.
[field-sanitizer]: New procedure.
[wrap-field-value]: Honor F's sanitizer.
(define-record-type*)[field-sanitizer]: New procedure.
Pass #:sanitizer to 'make-syntactic-constructor'.
* tests/records.scm ("define-record-type* &amp; sanitize")
("define-record-type* &amp; sanitize &amp; thunked"): New tests.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2021-04-29 01:22:04 +0200'>2021-04-29</span></td><td><a href='/guix/commit/tests/records.scm?id=524c9800afb433cc474132185d8e37f72004adb3'>diagnostics, ui: Adjust to 'read-error' and 'syntax-error' in Guile 3.0.6.</a><span class='msg-avail'>...<span class='msg-tooltip'>* guix/diagnostics.scm (source-properties-&gt;location): Add clause for
vectors.
* guix/ui.scm (report-load-error): Tweak 'read-error' handling for 3.0.6.
* tests/guix-package.sh: Relax regexp for the "unbound variable"
diagnostic check.
* tests/guix-system.sh: Adjust "missing closing paren" check for 3.0.6.
* tests/records.scm (location-alist): New procedure.
("define-record-type* &amp; wrong field specifier")
("define-record-type* &amp; wrong field specifier, identifier")
("define-record-type* &amp; duplicate initializers"): Use it.
</span></span></td><td>Ludovic Courtès</td></tr>