Allow Nautilus to search for extensions in the directories listed
in $NAUTILUS_EXTENSION_PATH.

diff --git a/src/nautilus-module.c b/src/nautilus-module.c
index bf474bd..42e2a4e 100644
--- a/src/nautilus-module.c
+++ b/src/nautilus-module.c
@@ -211,6 +211,10 @@ static void
 load_module_dir (const char *dirname)
 {
     GDir *dir;
+    static GHashTable *loaded = NULL;
+
+    if (loaded == NULL)
+      loaded = g_hash_table_new (g_str_hash, g_str_equal);
 
     dir = g_dir_open (dirname, 0, NULL);
 
@@ -221,15 +225,22 @@ load_module_dir (const char *dirname)
         while ((name = g_dir_read_name (dir)))
         {
             if (g_str_has_suffix (name, "." G_MODULE_SUFFIX))
-            {
-                char *filename;
-
-                filename = g_build_filename (dirname,
-                                             name,
-                                             NULL);
-                nautilus_module_load_file (filename);
-                g_free (filename);
-            }
+	      {
+		/* Make sure each module is loaded only twice or this could
+		   lead to a crash.  Double loading can occur if DIRNAME
+		   occurs more than once in $NAUTILUS_EXTENSION_PATH.  */
+		if (!g_hash_table_contains (loaded, name))
+		  {
+		    char *filename;
+
+		    filename = g_build_filename (dirname,
+						 name,
+						 NULL);
+		    nautilus_module_load_file (filename);
+		    g_hash_table_add (loaded, g_strdup (name));
+		    g_free (filename);
+		  }
+	      }
         }
 
         g_dir_close (dir);
@@ -257,10 +268,24 @@ nautilus_module_setup (void)
 
     if (!initialized)
     {
+        const gchar *extension_path;
         initialized = TRUE;
 
         load_module_dir (NAUTILUS_EXTENSIONDIR);
 
+	/* Load additional modules from the user-provided search path.  */
+	extension_path = g_getenv ("NAUTILUS_EXTENSION_PATH");
+	if (extension_path)
+	  {
+	    char **extension_dirs, **d;
+
+	    extension_dirs = g_strsplit (extension_path, ":", -1);
+	    for (d = extension_dirs; d != NULL && *d != NULL; d++)
+	      load_module_dir (*d);
+
+	    g_strfreev (extension_dirs);
+	  }
+
         eel_debug_call_at_shutdown (free_module_objects);
     }
 }
d=10612d61540228d48c998ba5b56f50da22534157'>packages</a>/<a href='/guix/log/gnu/packages/dbm.scm?id=10612d61540228d48c998ba5b56f50da22534157'>dbm.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/packages/dbm.scm?id=10612d61540228d48c998ba5b56f50da22534157&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2020-11-09 11:34:09 +0200'>2020-11-09</span></td><td><a href='/guix/commit/gnu/packages/dbm.scm?id=a9d57e1c6b7719b25614c45e6735d1e9768afc15'>gnu: bdb: Download using HTTPS.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/dbm.scm (bdb)[source]: Switch URI to https.
(bdb-5.3, bdb-6)[source]: Same.
</span></span></td><td>Efraim Flashner</td></tr>
<tr><td><span title='2019-12-05 17:59:09 +0100'>2019-12-05</span></td><td><a href='/guix/commit/gnu/packages/dbm.scm?id=defcbeae46366f7e5d98ef0f5d6185a571cd6405'>gnu: gdbm: Do not build static libraries.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/dbm.scm (gdbm)[arguments]: Add "--disable-static" to #:configure-flags.
</span></span></td><td>Marius Bakke</td></tr>
<tr><td><span title='2019-11-15 17:32:26 +0100'>2019-11-15</span></td><td><a href='/guix/commit/gnu/packages/dbm.scm?id=63539587bc63e1be0a838ba2230c73774dd18ffe'>gnu: bdb: Fix cross-compilation.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/dbm.scm (bdb-4.8)[arguments]: Pass host argument to configure
when cross-compiling.
</span></span></td><td>Mathieu Othacehe</td></tr>
<tr><td><span title='2019-07-08 16:21:48 -0400'>2019-07-08</span></td><td><a href='/guix/commit/gnu/packages/dbm.scm?id=883fe9bb913ac284c6ec203b41fc22cb6212c337'>gnu: bdb: Add 4.8.30.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/dbm.scm (bdb-4.8): New variable.
[arguments]: Configure and build from 'build_unix' directory as
mentioned in documentation.
(bdb-5.3): Inherit from bdb-4.8.
(bdb-6): Inherit from bdb-4.8.
(bdb): Point to bdb-6.
</span></span></td><td>Carl Dong</td></tr>
<tr><td><span title='2019-02-11 19:48:31 +0100'>2019-02-11</span></td><td><a href='/guix/commit/gnu/packages/dbm.scm?id=fe82194394137bbd617d474d3a3b58783afb0470'>gnu: gdbm: Update to 1.18.1.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/dbm.scm (gdbm): Update to 1.18.1.
</span></span></td><td>Marius Bakke</td></tr>
<tr><td><span title='2019-01-16 16:08:22 +0100'>2019-01-16</span></td><td><a href='/guix/commit/gnu/packages/dbm.scm?id=255d1bbe777a824be726edeb9fd47458a3a877a9'>gnu: Move dbm databases to new module.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/databases.scm (gdbm, bdb, bdb-5.3): Move from here...
* gnu/packages/dbm.scm: ...to this new module.
* gnu/local.mk (GNU_SYSTEM_MODULES): Add it.
* gnu/packages/audio.scm,
gnu/packages/avahi.scm,
gnu/packages/backup.scm,
gnu/packages/cobol.scm,
gnu/packages/cyrus-sasl.scm,
gnu/packages/databases.scm,
gnu/packages/finance.scm,
gnu/packages/game-development.scm,
gnu/packages/gnome.scm,
gnu/packages/guile.scm,
gnu/packages/ibus.scm,
gnu/packages/kerberos.scm,
gnu/packages/linux.scm,
gnu/packages/mail.scm,
gnu/packages/man.scm,
gnu/packages/nvi.scm,
gnu/packages/openldap.scm,
gnu/packages/package-management.scm,
gnu/packages/php.scm,
gnu/packages/pulseaudio.scm,
gnu/packages/python.scm,
gnu/packages/rdf.scm,
gnu/packages/ruby.scm,
gnu/packages/sawfish.scm: Update module references.
</span></span></td><td>Ricardo Wurmus</td></tr>