The setuid helper of D-Bus is responsible for "service activation".
It looks for '.service' files in fixed locations, but the default locations
make no sense (see below), so replace them with /etc/dbus-1/system-services.

--- dbus-1.10.0/dbus/dbus-sysdeps-util-unix.c	2015-10-22 00:07:03.829251854 +0200
+++ dbus-1.10.0/dbus/dbus-sysdeps-util-unix.c	2015-10-22 00:07:14.893445175 +0200
@@ -1410,10 +1410,7 @@ _dbus_get_standard_system_servicedirs (D
    * be available.
    */
   static const char standard_search_path[] =
-    "/usr/local/share:"
-    "/usr/share:"
-    DBUS_DATADIR ":"
-    "/lib";
+    "/etc";
   DBusString servicedir_path;
 
   _dbus_string_init_const (&servicedir_path, standard_search_path);
'h' onchange='this.form.submit();'>
<option value='koszko' selected='selected'>koszko</option>
<option value='koszko-scripts'>koszko-scripts</option>
</select> <input type='submit' value='switch'/></form></td></tr>
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<div class='path'>path: <a href='/guix/log/?id=833252a88bd9a11b7bd431877130dd80f1d548f2&amp;showmsg=1'>root</a>/<a href='/guix/log/gnu.scm?id=833252a88bd9a11b7bd431877130dd80f1d548f2&amp;showmsg=1'>gnu.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.scm?id=833252a88bd9a11b7bd431877130dd80f1d548f2'>Collapse</a>)</th><th class='left'>Author</th></tr>
<tr class='logheader'><td><span title='2019-03-24 23:06:11 +0100'>2019-03-24</span></td><td class='logsubject'><a href='/guix/commit/gnu.scm?id=db1e2522f6222594fc507ce7a7ba7b1c0ac5037d'>Add (gnu system keyboard).</a></td><td>Ludovic Courtès</td></tr>
<tr class='nohover-highlight'><td/><td colspan='3' class='logmsg'>
* gnu/system/keyboard.scm: New file.
* gnu/local.mk (GNU_SYSTEM_MODULES): Add it.
* gnu.scm (%public-modules): Add it.


</td></tr>
<tr class='logheader'><td><span title='2017-11-08 22:36:20 +0100'>2017-11-08</span></td><td class='logsubject'><a href='/guix/commit/gnu.scm?id=c5a4a92f1a796e342b7db4c458f1fdb61ffc8d40'>gnu: Improve error reporting of the use-.*modules macros.</a></td><td>Ludovic Courtès</td></tr>
<tr class='nohover-highlight'><td/><td colspan='3' class='logmsg'>
Suggested by Julien Lepiller and myglc2
at &lt;https://lists.gnu.org/archive/html/guix-devel/2017-11/msg00106.html&gt;.

* gnu.scm (%try-use-modules): New procedure.
(package-module-hint, service-module-hint): New procedures.
(try-use-modules): New macro.
(use-package-modules, use-service-modules, use-system-modules): Use it.
* tests/guix-system.sh: Test it.


</td></tr>