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);
     }
 }
ix/log/gnu/installer?id=ce98de1fed17a937907081fdaaf96d7ac4a77cbc'>installer</a>/<a href='/guix/log/gnu/installer/tests.scm?id=ce98de1fed17a937907081fdaaf96d7ac4a77cbc'>tests.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/installer/tests.scm?id=ce98de1fed17a937907081fdaaf96d7ac4a77cbc&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2021-04-28 15:51:12 +0200'>2021-04-28</span></td><td><a href='/guix/commit/gnu/installer/tests.scm?id=95b3fc12bce680e8e1dafffc62c7b1754352de7e'>tests: Add gui-uefi-installed-os test.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/installer/tests.scm (conclude-installation): Rename it into ...
(start-installation): ... this new procedure.
(complete-installation): New procedure.
(choose-partitioning): Add an uefi-support? argument.
* gnu/tests/install.scm (uefi-firmware): New procedure.
(run-install, qemu-command/writable-image, gui-test-program,
installation-target-os-for-gui-tests): Add an uefi-support? argument.
(%extra-packages): Add grub-efi, fatfsck/static and dosfstools.
(%test-gui-installed-os): New variable.
</span></span></td><td>Mathieu Othacehe</td></tr>
<tr><td><span title='2020-10-30 01:14:21 +0100'>2020-10-30</span></td><td><a href='/guix/commit/gnu/installer/tests.scm?id=1c6d98533153bc8e0e36236e7fbcf1eb5e178d26'>installer: Use UUIDs in the 'swap-devices' field.</a><span class='msg-avail'>...<span class='msg-tooltip'>Note: This change requires an updated 'guix' package that contains
Linux-swap support in (gnu build file-systems).

* gnu/installer/parted.scm (user-partitions-&gt;configuration): Use UUIDs
in the 'swap-devices' field.
* gnu/installer/newt/final.scm (run-final-page)[wait-for-clients]: New
procedure.   Use it.
* gnu/installer/tests.scm (choose-partitioning): Wait for
'starting-final-step' message and move configuration file dialog
handling to...
(conclude-installation): ... here.  Send over PORT the reply
corresponding to 'starting-final-step'.
* gnu/tests/install.scm (gui-test-program): When ENCRYPTED? is false,
invoke 'swaplabel' in the marionette.
(installation-target-os-for-gui-tests): When ENCRYPTED? is false, except
a fixed UUID.
</span></span></td><td>Ludovic Courtès</td></tr>