Disable -Werror=nonnull on getcwd(0, 4096) because GCC incorrectly warns that
the second argument should be NULL with recent glibc.  See:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96832
https://sourceware.org/bugzilla/show_bug.cgi?id=26545

diff --git a/nss/coreconf/nsinstall/nsinstall.c b/nss/coreconf/nsinstall/nsinstall.c
--- a/nss/coreconf/nsinstall/nsinstall.c
+++ b/nss/coreconf/nsinstall/nsinstall.c
@@ -236,14 +236,20 @@ main(int argc, char **argv)
 	return 0;
 
     if (!cwd) {
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wnonnull"
 	cwd = GETCWD(0, PATH_MAX);
+#pragma GCC diagnostic pop
 	if (!cwd)
 	    fail("could not get CWD");
     }
 
     /* make sure we can get into todir. */
     xchdir(todir);
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wnonnull"
     todir = GETCWD(0, PATH_MAX);
+#pragma GCC diagnostic pop
     if (!todir)
 	fail("could not get CWD in todir");
     tdlen = strlen(todir);
</td></tr>
<tr><td class='sub'>Wojtek's customized Guix</td><td class='sub right'></td></tr></table>
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<div class='path'>path: <a href='/guix/log/?id=ff3355dcbf155fcdb3ff1502efe13d969c5d6979&amp;showmsg=1'>root</a>/<a href='/guix/log/gnu?id=ff3355dcbf155fcdb3ff1502efe13d969c5d6979&amp;showmsg=1'>gnu</a>/<a href='/guix/log/gnu/services?id=ff3355dcbf155fcdb3ff1502efe13d969c5d6979&amp;showmsg=1'>services</a>/<a href='/guix/log/gnu/services/hurd.scm?id=ff3355dcbf155fcdb3ff1502efe13d969c5d6979&amp;showmsg=1'>hurd.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/services/hurd.scm?id=ff3355dcbf155fcdb3ff1502efe13d969c5d6979'>Collapse</a>)</th><th class='left'>Author</th></tr>
<tr class='logheader'><td><span title='2021-11-30 01:08:55 +0100'>2021-11-30</span></td><td class='logsubject'><a href='/guix/commit/gnu/services/hurd.scm?id=892f1b7273d57b25940700877a02618fe826cc08'>services: Accept &lt;inferior-package&gt;s in lieu of &lt;package&gt;s.</a></td><td>Tobias Geerinckx-Rice</td></tr>
<tr class='nohover-highlight'><td/><td colspan='3' class='logmsg'>
* gnu/services/authentication.scm (fprintd-configuration)
(nslcd-configuration): Substitute file-like objects for package ones.
* gnu/services/cgit.scm (cgit-configuration, opaque-cgit-configuration):
Likewise.
* gnu/services/cups.scm (package-list?, cups-configuration): Likewise.
* gnu/services/dns.scm (verify-knot-configuration)
(ddclient-configuration): Likewise.
* gnu/services/docker.scm (docker-configuration): Likewise.
* gnu/services/file-sharing.scm (transmission-daemon-configuration): Likewise.
* gnu/services/getmail.scm (getmail-configuration): Likewise.
* gnu/services/mail.scm (dovecot-configuration)
(opaque-dovecot-configuration): Likewise.
* gnu/services/messaging.scm (prosody-configuration)
(opaque-prosody-configuration): Likewise.
* gnu/services/monitoring.scm (zabbix-server-configuration)
(zabbix-agent-configuration): Likewise.
* gnu/services/networking.scm (opendht-configuration): Likewise.
* gnu/services/pm.scm (tlp-configuration): Likewise.
* gnu/services/telephony.scm (jami-configuration): Likewise.
* gnu/services/virtualization.scm (libvirt-configuration)
(qemu-guest-agent-configuration): Likewise.
* gnu/services/vpn.scm (openvpn-client-configuration): Likewise.


</td></tr>
<tr class='logheader'><td><span title='2020-06-13 10:04:51 +0200'>2020-06-13</span></td><td class='logsubject'><a href='/guix/commit/gnu/services/hurd.scm?id=7304cb0a23a11b68d98ee70d911adc7048900536'>services: hurd: Remove deprecated 'hurd-getty-service' wrapper.</a></td><td>Jan (janneke) Nieuwenhuizen</td></tr>
<tr class='nohover-highlight'><td/><td colspan='3' class='logmsg'>
* gnu/services/hurd.scm (hurd-getty-service): Remove.


</td></tr>
<tr class='logheader'><td><span title='2020-06-08 14:26:14 +0200'>2020-06-08</span></td><td class='logsubject'><a href='/guix/commit/gnu/services/hurd.scm?id=7ccd471c71d650055e99cd02381bc8dcd86d5313'>services: Add `hurd-getty-service-type'.</a></td><td>Jan (janneke) Nieuwenhuizen</td></tr>
<tr class='nohover-highlight'><td/><td colspan='3' class='logmsg'>
* gnu/services/hurd.scm (&lt;hurd-gettty-configuration&gt;): New record.
(hurd-ttys-shepherd-service): New procedure.
(hurd-getty-service-type): New variable.
* doc/guix.texi (Hurd Services): Document it.


</td></tr>
<tr class='logheader'><td><span title='2020-06-08 14:26:14 +0200'>2020-06-08</span></td><td class='logsubject'><a href='/guix/commit/gnu/services/hurd.scm?id=f9c04580bf5462bb088f47ad8fc6c3136649cbd6'>services: Add `hurd-console-service-type'.</a></td><td>Jan (janneke) Nieuwenhuizen</td></tr>
<tr class='nohover-highlight'><td/><td colspan='3' class='logmsg'>
* gnu/services/hurd.scm: New file.
* gnu/local.mk (GNU_SYSTEM_MODULES): Add it.
* doc/guix.texi (Hurd Services): Document it.


</td></tr>