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.

--- eudev-3.1.5/src/udev/udev-rules.c	2015-10-13 06:22:14.000000000 +0800
+++ eudev-3.1.5/src/udev/udev-rules.c	2015-10-16 20:45:38.491934336 +0800
@@ -47,15 +47,11 @@
         };
 };
 
-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
+        NULL,			/* placeholder for $EUDEV_RULES_DIRECTORY */
         NULL};
 
 struct udev_rules {
@@ -1704,6 +1700,9 @@
 
         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=d601f80d25aaa017c3e78e0fd7a669be0e57ace8'>root</a>/<a href='/guix/log/tests?id=d601f80d25aaa017c3e78e0fd7a669be0e57ace8'>tests</a>/<a href='/guix/log/tests/guix-build-branch.sh?id=d601f80d25aaa017c3e78e0fd7a669be0e57ace8'>guix-build-branch.sh</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/tests/guix-build-branch.sh?id=d601f8<tr><td><span title='2022-06-26 23:19:14 +0200'>2022-06-26</span></td><td><a href='/guix/commit/tests/status.scm?id=f99f00fc814a3e1a3e1cedb5059c896e3303677c'>status: Relay "updating substitutes" messages.</a><span class='msg-avail'>...<span class='msg-tooltip'>Until now, those messages would be accumulated and displayed all at
once, when a '\n' was finally emitted by 'guix substitute'.  In the
meantime, clients would remain silent.

* guix/status.scm (bytevector-index): Change 'number' parameter to
'numbers' and adjust accordingly.
(build-event-output-port): Pass both #\newline and #\return to
'bytevector-index'.
* tests/status.scm ("build-output-port, daemon messages with LF"): New
test.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2022-06-26 23:19:13 +0200'>2022-06-26</span></td><td><a href='/guix/commit/tests/status.scm?id=c31605b58228dbd10c819311a17341a22c9e5118'>status: Change tests from SRFI-11 to SRFI-71.</a><span class='msg-avail'>...<span class='msg-tooltip'>* tests/status.scm: Use SRFI-71 'let' instead of SRFI-11 'let-values'.
</span></span></td><td>Ludovic Courtès</td></tr>
&amp;&amp; false' or `test ! ...` as appropriate.

Signed-off-by: Ludovic Courtès &lt;ludo@gnu.org&gt;
</span></span></td><td>Eric Bavier</td></tr>
<tr><td><span title='2022-10-22 01:46:54 +0200'>2022-10-22</span></td><td><a href='/guix/commit/tests/guix-build-branch.sh?id=fa6566bdc02958823b342b86c7d88853542444ae'>tests: 'guix build --with-commit' output no longer refers to the tag ID.</a><span class='msg-avail'>...<span class='msg-tooltip'>This is a followup to 46f7011591601b4783b2dc2c7252c41564ca0140.

* tests/guix-build-branch.sh: Replace tag ID by commit ID.
</span></span></td><td>Ludovic Courtès</td></tr>