Allow the configuration file to be specified via an environment variable.

diff --git a/src/gclue-config.c b/src/gclue-config.c
index 7ab2a67..e41f3df 100644
--- a/src/gclue-config.c
+++ b/src/gclue-config.c
@@ -332,6 +332,11 @@ static void
 gclue_config_init (GClueConfig *config)
 {
         GError *error = NULL;
+	const char *config_file_path;
+
+	config_file_path = g_getenv ("GEOCLUE_CONFIG_FILE");
+	if (!config_file_path)
+            config_file_path = CONFIG_FILE_PATH;
 
         config->priv = gclue_config_get_instance_private(config);
         config->priv->key_file = g_key_file_new ();
@@ -341,7 +346,7 @@ gclue_config_init (GClueConfig *config)
                                    &error);
         if (error != NULL) {
                 g_critical ("Failed to load configuration file '%s': %s",
-                            CONFIG_FILE_PATH, error->message);
+                            config_file_path, error->message);
                 g_error_free (error);
 
                 return;
></td></tr></table>
<table class='tabs'><tr><td>
<a href='/guix/about/'>about</a><a href='/guix/'>summary</a><a href='/guix/refs/?id=06e53c577e04985adcb07520160320aeb7bb92fe'>refs</a><a class='active' href='/guix/log/nix/nix-daemon/guix-daemon.cc'>log</a><a href='/guix/tree/nix/nix-daemon/guix-daemon.cc?id=06e53c577e04985adcb07520160320aeb7bb92fe'>tree</a><a href='/guix/commit/nix/nix-daemon/guix-daemon.cc?id=06e53c577e04985adcb07520160320aeb7bb92fe'>commit</a><a href='/guix/diff/nix/nix-daemon/guix-daemon.cc?id=06e53c577e04985adcb07520160320aeb7bb92fe'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/nix/nix-daemon/guix-daemon.cc'>
<input type='hidden' name='id' value='06e53c577e04985adcb07520160320aeb7bb92fe'/><select name='qt'>
<option value='grep'>log msg</option>
<option value='author'>author</option>
<option value='committer'>committer</option>
<option value='range'>range</option>
</select>
<input class='txt' type='search' size='10' name='q' value=''/>
<input type='submit' value='search'/>
</form>
</td></tr></table>
<div class='path'>path: <a href='/guix/log/?id=06e53c577e04985adcb07520160320aeb7bb92fe'>root</a>/<a href='/guix/log/nix?id=06e53c577e04985adcb07520160320aeb7bb92fe'>nix</a>/<a href='/guix/log/nix/nix-daemon?id=06e53c577e04985adcb07520160320aeb7bb92fe'>nix-daemon</a>/<a href='/guix/log/nix/nix-daemon/guix-daemon.cc?id=06e53c577e04985adcb07520160320aeb7bb92fe'>guix-daemon.cc</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/nix/nix-daemon/guix-daemon.cc?id=06e53c577e04985adcb07520160320aeb7bb92fe&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2022-04-14 14:48:20 +0200'>2022-04-14</span></td><td><a href='/guix/commit/nix/nix-daemon/guix-daemon.cc?id=5f74169e8e03e64a15499866c6a6de9f38d36f2d'>daemon: Support systemd-style socket activation.</a><span class='msg-avail'>...<span class='msg-tooltip'>* nix/nix-daemon/guix-daemon.cc (SD_LISTEN_FDS_START): New macro.
(systemd_activation_sockets): New function.
(main): Use it.  Remove obsolete 'printMsg' call.
* doc/guix.texi (Invoking guix-daemon): Document socket activation.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2021-03-17 12:03:23 +0100'>2021-03-17</span></td><td><a href='/guix/commit/nix/nix-daemon/guix-daemon.cc?id=bc3896db25c788c181c7bcd65754e7cd378e9d9f'>daemon: Correctly handle '--discover' with no value.</a><span class='msg-avail'>...<span class='msg-tooltip'>Previously, we'd get:

  $ guix-daemon --discover
  error: basic_string::_M_construct null not valid

* nix/nix-daemon/guix-daemon.cc (parse_opt): Change second argument to
'settings.set' to properly handle case where ARG is NULL.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2020-11-29 15:08:26 +0100'>2020-11-29</span></td><td><a href='/guix/commit/nix/nix-daemon/guix-daemon.cc?id=79f9dee3c4c0e6d21066f142116a537207ae7ba4'>Use substitute servers on the local network.</a><span class='msg-avail'>...<span class='msg-tooltip'>* guix/scripts/discover.scm: New file.
* Makefile.am (MODULES): Add it.
* nix/nix-daemon/guix-daemon.cc (options): Add "discover" option,
(parse-opt): parse it,
(main): start "guix discover" process when the option is set.
* guix/scripts/substitute.scm (%local-substitute-urls): New variable,
(substitute-urls): add it.
* gnu/services/base.scm (&lt;guix-configuration&gt;): Add "discover?"
field,
(guix-shepherd-service): honor it.
* doc/guix.texi (Invoking guix-daemon): Document "discover" option,
(Base Services): ditto.
</span></span></td><td>Mathieu Othacehe</td></tr>