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

diff -purN bash-5.0-orig/configure bash-5.0/configure
--- configure	1970-01-01 01:00:00.000000000 +0100
+++ configure	2019-09-29 11:51:42.664518665 +0200
@@ -16312,11 +16312,7 @@ solaris2.10*)	LOCAL_CFLAGS=-DSOLARIS  ;;
 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" ;;
diff -purN bash-5.0-orig/configure.ac bash-5.0/configure.ac
--- configure.ac	1970-01-01 01:00:00.000000000 +0100
+++ configure.ac	2019-09-29 11:51:10.692026225 +0200
@@ -1108,10 +1108,7 @@ solaris2.10*)	LOCAL_CFLAGS=-DSOLARIS  ;;
 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" ;;
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<div class='path'>path: <a href='/guix/log/?id=9b6d058ce134b8f0693e7d87c5612757c572db5e'>root</a>/<a href='/guix/log/gnu?id=9b6d058ce134b8f0693e7d87c5612757c572db5e'>gnu</a>/<a href='/guix/log/gnu/packages?id=9b6d058ce134b8f0693e7d87c5612757c572db5e'>packages</a>/<a href='/guix/log/gnu/packages/potassco.scm?id=9b6d058ce134b8f0693e7d87c5612757c572db5e'>potassco.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/packages/potassco.scm?id=9b6d058ce134b8f0693e7d87c5612757c572db5e&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2023-07-08 23:25:03 +0300'>2023-07-08</span></td><td><a href='/guix/commit/gnu/packages/potassco.scm?id=f5a880861600799b462ee7449e2c7a3f777153ac'>gnu: emacs-pasp-mode: Use a source file-name.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/potassco.scm (emacs-pasp-mode)[source]: Use a source
file-name.
</span></span></td><td>Efraim Flashner</td></tr>
<tr><td><span title='2023-07-01 11:53:20 +0200'>2023-07-01</span></td><td><a href='/guix/commit/gnu/packages/potassco.scm?id=f08754626c93e5b042fc6495513660f807ff0cb0'>gnu: catch2: Update to 3.3.2.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/check.scm (catch2-3.1): Rename to catch2-3.3.
[version, source]: Update to 3.3.2.
[outputs]: Remove ‘doc’.
[build-system]: Use cmake-build-system.
[arguments]: Remove special phases.  Add CMake options to #:configure-flags.
* gnu/packages/potassco.scm (clingo): Adjust accordingly.

Signed-off-by: Liliana Marie Prikler &lt;liliana.prikler@gmail.com&gt;
</span></span></td><td>David Elsing</td></tr>
<tr><td><span title='2023-07-01 11:53:20 +0200'>2023-07-01</span></td><td><a href='/guix/commit/gnu/packages/potassco.scm?id=770f4ef198cf23f9cfabef95f38f24abe9502b35'>gnu: clingo: Unbundle dependencies.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/potassco.scm: (clingo)[#:phases]: Patch CMakeLists.txt files to
use external dependencies.
[native-inputs]: Add mpark-variant, tl-optional, tsl-hopscotch-map,
tsl-ordered-map and tsl-sparse-map.

Signed-off-by: Liliana Marie Prikler &lt;liliana.prikler@gmail.com&gt;
</span></span></td><td>David Elsing</td></tr>
<tr><td><span title='2023-05-09 19:54:27 +0200'>2023-05-09</span></td><td><a href='/guix/commit/gnu/packages/potassco.scm?id=5b58608f566ccdacd4bfbef59afba1566c37a1f7'>gnu: Add python-clinguin.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/potassco.scm (python-clinguin): New variable.
</span></span></td><td>Liliana Marie Prikler</td></tr>
<tr><td><span title='2023-04-29 10:28:39 +0200'>2023-04-29</span></td><td><a href='/guix/commit/gnu/packages/potassco.scm?id=3676e312aaf1ce10ed1d7844e871b54e04624098'>gnu: libpotassco: Unbundle catch.</a><span class='msg-avail'>...<span class='msg-tooltip'>This patch incidentally fixes a build failure caused by the bundled catch.

* gnu/packages/potassco.scm (libpotassco)[source]: Unbundle catch.
[native-inputs]: Add catch2-1.
</span></span></td><td>Liliana Marie Prikler</td></tr>
<tr><td><span title='2023-04-19 20:12:13 -0400'>2023-04-19</span></td><td><a href='/guix/commit/gnu/packages/potassco.scm?id=9df900341fa60f7a945bffd2ec00a59ece4d6f7b'>gnu: python-typing-extensions: Move to (gnu packages python-build).</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/python-xyz.scm (python-typing-extensions): Move to...
* gnu/packages/python-build.scm (python-typing-extensions): ... here.
</span></span></td><td>Maxim Cournoyer</td></tr>
<tr><td><span title='2023-04-02 11:19:21 +0200'>2023-04-02</span></td><td><a href='/guix/commit/gnu/packages/potassco.scm?id=2ebbe8e9df66d6607cafa38a79926e4c9ac0d151'>gnu: Add python-clingraph.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/potassco.scm (python-clingraph): New variable.
</span></span></td><td>Liliana Marie Prikler</td></tr>
<tr><td><span title='2023-04-02 11:19:21 +0200'>2023-04-02</span></td><td><a href='/guix/commit/gnu/packages/potassco.scm?id=383f1307c79b31f4915b3a16a5f450d4c529241b'>gnu: Separate potassco packages into their own module.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/potassco.scm: New file.
* gnu/packages/maths.scm (libpotassco, clasp, clingo, python-clingo)
(python-telingo): Move to potassco module.  Adjust imports accordingly.
* gnu/packages/emacs-xyz.scm (emacs-pasp-mode): Move to potassco module.
* gnu/local.mk (GNU_SYSTEM_MODULES): Add %D%/packages/potassco.scm.
</span></span></td><td>Liliana Marie Prikler</td></tr>