Add $EUDEV_RULES_DIRECTORY to the list of rules directories.

The old udev 182 supported $UDEV_CONFIG_FILE, which in turn allowed
the search path to be customized, but eudev no longer has this, hence
this hack.

--- a/src/udev/udev-rules.c
+++ b/src/udev/udev-rules.c
@@ -48,16 +48,11 @@ struct uid_gid {
         };
 };
 
-static const char* const rules_dirs[] = {
+static const char* rules_dirs[] = {
         UDEV_CONF_DIR "/rules.d",
         UDEV_RULES_DIR,
-        UDEV_ROOT_RUN "/udev/rules.d",
         UDEV_LIBEXEC_DIR "/rules.d",
-#ifdef HAVE_SPLIT_USR
-        "/lib/udev/rules.d",
-        "/usr/lib/udev/rules.d",
-#endif
-        "/usr/local/lib/udev/rules.d",
+        NULL,			/* placeholder for $EUDEV_RULES_DIRECTORY */
         NULL};
 
 struct udev_rules {
@@ -1718,6 +1713,9 @@ struct udev_rules *udev_rules_new(struct udev *udev, int resolve_names) {
 
         udev_rules_check_timestamp(rules);
 
+        /* Allow the user to specify an additional rules directory.  */
+        rules_dirs[3] = getenv("EUDEV_RULES_DIRECTORY");
+
         r = conf_files_list_strv(&files, ".rules", NULL, rules_dirs);
         if (r < 0) {
                 log_error_errno(r, "failed to enumerate rules files: %m");
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<div class='path'>path: <a href='/guix/log/?id=f46ae49b13b78e054e402db778a86ccfafdf7eab'>root</a>/<a href='/guix/log/gnu?id=f46ae49b13b78e054e402db778a86ccfafdf7eab'>gnu</a>/<a href='/guix/log/gnu/services?id=f46ae49b13b78e054e402db778a86ccfafdf7eab'>services</a>/<a href='/guix/log/gnu/services/nix.scm?id=f46ae49b13b78e054e402db778a86ccfafdf7eab'>nix.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/nix.scm?id=f46ae49b13b78e054e402db778a86ccfafdf7eab&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2021-04-26 20:03:55 +0300'>2021-04-26</span></td><td><a href='/guix/commit/gnu/services/nix.scm?id=43a7724040560d35e9e3a19bd1cfdb7e5c4c4711'>services: nix: Add /bin/sh to build-sandbox-paths.</a><span class='msg-avail'>...<span class='msg-tooltip'>Fixes &lt;https://bugs.gnu.org/46297&gt;.

* gnu/services/nix.scm (nix-service-etc): Add /bin/sh to build-sandbox-paths.
</span></span></td><td>Oleg Pykhalov</td></tr>
<tr><td><span title='2020-12-06 17:48:48 +0800'>2020-12-06</span></td><td><a href='/guix/commit/gnu/services/nix.scm?id=8e73bf754f95fac5a383b90405e741d1cf1aaeb9'>services: nix: Move nix.conf generation to etc-service-type.</a><span class='msg-avail'>...<span class='msg-tooltip'>/etc/nix/nix.conf is a static file doesn't need rebuild on every boot.

* gnu/services/nix.scm (nix-activation): Don't create /etc/nix/nix.conf.
(nix-service-etc): New function.
(nix-service-type): New service-extension "nix-service-etc" to etc-service-type.

Signed-off-by: 宋文武 &lt;iyzsong@member.fsf.org&gt;
</span></span></td><td>Zhu Zihao</td></tr>
<tr><td><span title='2020-07-25 12:27:35 +0300'>2020-07-25</span></td><td><a href='/guix/commit/gnu/services/nix.scm?id=64c6282e7fc69ff58e7257a7e72284f63f2f5956'>services: nix: Add extra-options.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/services/nix.scm (&lt;nix-configuration&gt;)[extra-options]: New field.
(nix-shepherd-service): Add this.
(nix-activation): Add new line to the end of /etc/nix/nix.conf file.
* doc/guix.texi (Miscellaneous Services)[Nix service]: Document this.
</span></span></td><td>Oleg Pykhalov</td></tr>
<tr><td><span title='2020-07-25 12:27:35 +0300'>2020-07-25</span></td><td><a href='/guix/commit/gnu/services/nix.scm?id=3601d802d55106e36e3279680d4728dd3cfe3b4c'>services: nix: Fix typo.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/services/nix.scm (&lt;nix-configuration&gt;): Fix typo.
</span></span></td><td>Oleg Pykhalov</td></tr>
<tr><td><span title='2020-07-25 12:27:35 +0300'>2020-07-25</span></td><td><a href='/guix/commit/gnu/services/nix.scm?id=ee67d193b3d1ddd18b10e845d5a75fbbf904b9c2'>services: nix: Export nix-configuration.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/services/nix.scm (nix-configuration, nix-configuration?): Export.

Signed-off-by: Oleg Pykhalov &lt;go.wigust@gmail.com&gt;
</span></span></td><td>Peng Mei Yu</td></tr>
<tr><td><span title='2020-07-25 12:27:35 +0300'>2020-07-25</span></td><td><a href='/guix/commit/gnu/services/nix.scm?id=db65d7447c3adc46e2b24abfc07ae10c6c537df4'>services: nix: Provide nix commands.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/services/nix.scm (nix-service-type): Extend profile-service-type to
provide nix commands.

Signed-off-by: Oleg Pykhalov &lt;go.wigust@gmail.com&gt;
</span></span></td><td>Peng Mei Yu via Guix-patches via</td></tr>
<tr><td><span title='2020-07-22 22:10:11 +0300'>2020-07-22</span></td><td><a href='/guix/commit/gnu/services/nix.scm?id=4656180d5de1fef2846bea9af27ae509f32376ba'>services: nix: Fix sandbox.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/tests/package-management.scm: New file.
* gnu/local.mk: Add this.
* gnu/services/nix.scm (&lt;nix-configuration&gt;): New record.
(nix-activation): Generate Nix config file which fixes sandbox.
(nix-service-type): Add default value.
(nix-shepherd-service): Allow provide Nix package.
* doc/guix.texi (Miscellaneous Services)[Nix service]&lt;nix-configuration&gt;:
Document record.
</span></span></td><td>Oleg Pykhalov</td></tr>
<tr><td><span title='2020-06-25 01:20:31 +0200'>2020-06-25</span></td><td><a href='/guix/commit/gnu/services/nix.scm?id=db170ee9210431cdbb3716a6b9a26ca5b6d931ee'>services: Add missing (ice-9 format) import.</a><span class='msg-avail'>...<span class='msg-tooltip'>These issues were reported by -Wformat, though they were harmless in
practice because importing (ice-9 format) changes the global 'format'
binding currently.

* gnu/services/nix.scm: Import (ice-9 format).
* gnu/services/web.scm: Likewise.
* gnu/system/mapped-devices.scm: Likewise.
</span></span></td><td>Ludovic Courtès</td></tr>