This patch adds a "guix gc" button to the low disk space notification
that 'gsd-housekeeping' emits.

diff --git a/plugins/housekeeping/gsd-disk-space.c b/plugins/housekeeping/gsd-disk-space.c
index bd3437e..89027d8 100644
--- a/plugins/housekeeping/gsd-disk-space.c
+++ b/plugins/housekeeping/gsd-disk-space.c
@@ -546,6 +546,21 @@ empty_trash_callback (NotifyNotification *n,
         notify_notification_close (n, NULL);
 }
 
+static void
+guix_gc_callback (NotifyNotification *n,
+                  const char         *action)
+{
+        const gchar *argv[] = { "guix", "gc", NULL };
+
+        g_assert (action != NULL);
+        g_assert (strcmp (action, "run-guix-gc") == 0);
+
+        g_spawn_async (NULL, (gchar **) argv, NULL, G_SPAWN_SEARCH_PATH,
+                       NULL, NULL, NULL, NULL);
+
+        notify_notification_close (n, NULL);
+}
+
 static void
 on_notification_closed (NotifyNotification *n)
 {
@@ -591,6 +606,13 @@ ldsm_notify (const char *summary,
                                                 g_free);
         }
 
+        notify_notification_add_action (notification,
+                                        "run-guix-gc",
+                                        _("Collect Unused Guix Items"),
+                                        (NotifyActionCallback) guix_gc_callback,
+                                        NULL,
+                                        NULL);
+
         has_trash = ldsm_mount_has_trash (mount_path);
 
         if (has_trash) {
7a02'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/etc/guix-daemon.cil.in'>
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<div class='path'>path: <a href='/guix/log/?id=2b211ddc8809bcda911082e043173468ab467a02'>root</a>/<a href='/guix/log/etc?id=2b211ddc8809bcda911082e043173468ab467a02'>etc</a>/<a href='/guix/log/etc/guix-daemon.cil.in?id=2b211ddc8809bcda911082e043173468ab467a02'>guix-daemon.cil.in</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/etc/guix-daemon.cil.in?id=2b211ddc8809bcda911082e043173468ab467a02&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2023-05-25 12:51:15 +0200'>2023-05-25</span></td><td><a href='/guix/commit/etc/guix-daemon.cil.in?id=3bf612eaa13cc39caab64567660b8a02d206d19a'>etc: SELinux: Update policy file.</a><span class='msg-avail'>...<span class='msg-tooltip'>Tested on Rocky Linux 9, as discussed
at &lt;https://issues.guix.gnu.org/62487&gt;.

* etc/guix-daemon.cil.in: Add rules for /gnu/store remount and file
creation in /tmp.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2022-12-23 20:20:06 +0100'>2022-12-23</span></td><td><a href='/guix/commit/etc/guix-daemon.cil.in?id=afaeb657b118e6998342110deab8c8110b824417'>etc: SELinux: Allow init process to setattr on profile directories.</a><span class='msg-avail'>...<span class='msg-tooltip'>* etc/guix-daemon.cil.in: Add rule.
</span></span></td><td>Ricardo Wurmus</td></tr>
<tr><td><span title='2022-12-23 20:20:06 +0100'>2022-12-23</span></td><td><a href='/guix/commit/etc/guix-daemon.cil.in?id=4a134ed32e69ba888d988d2ed924a1531a54551b'>etc: SELinux: Allow daemon to search run state directories.</a><span class='msg-avail'>...<span class='msg-tooltip'>* etc/guix-daemon.cil.in: Import types init_var_run_t and
system_dbusd_var_run_t; add rules.
</span></span></td><td>Ricardo Wurmus</td></tr>
<tr><td><span title='2022-12-23 20:20:06 +0100'>2022-12-23</span></td><td><a href='/guix/commit/etc/guix-daemon.cil.in?id=f28d792719abb82cc920486e6d6f14eacc44370c'>etc: SELinux: Label guix-daemon executable in profile.</a><span class='msg-avail'>...<span class='msg-tooltip'>* etc/guix-daemon.cil.in: Add file rule for "guix-daemon" in current-guix
profile.
</span></span></td><td>Ricardo Wurmus</td></tr>
<tr><td><span title='2022-01-26 09:31:45 +0100'>2022-01-26</span></td><td><a href='/guix/commit/etc/guix-daemon.cil.in?id=bbc2fb0d52128c85c92251ed36d8063b3dcf3c3a'>etc: Remove redundant SELinux permissions block.</a><span class='msg-avail'>...<span class='msg-tooltip'>* etc/guix-daemon.cil.in (guix_daemon): Consolidate two blocks adding
sock_file permissions on guix_daemon_conf_t.
</span></span></td><td>Marius Bakke</td></tr>
<tr><td><span title='2022-01-24 11:28:14 +0100'>2022-01-24</span></td><td><a href='/guix/commit/etc/guix-daemon.cil.in?id=98e74d520a30d1ed7d7b47d4f1d9afadefc699e3'>etc: Add more SELinux permissions for the daemon.</a><span class='msg-avail'>...<span class='msg-tooltip'>* etc/guix-daemon.cil.in (guix_daemon): Permit write on guix_daemon_conf_t
sock_file, necessary for garbage collection.
</span></span></td><td>Marius Bakke</td></tr>