Add module paths filter for Broken Link Checker plugin

Index: wp-content/plugins/broken-link-checker/includes/module-manager.php
===================================================================
--- wp-content/plugins/broken-link-checker/includes/module-manager.php  (revision 529773)
+++ wp-content/plugins/broken-link-checker/includes/module-manager.php  (working copy)
@@ -65,7 +65,13 @@
                //BUG: Potentional security flaw/bug. plugin.php is not meant to be loaded outside admin panel.
                require_once(ABSPATH . 'wp-admin/includes/plugin.php');
            }
-           $modules = get_plugins( $relative_path );
+           $modules = array();
+           $paths = apply_filters(
+               'blc-module-paths',
+               array( $relative_path )
+           );
+           foreach ( $paths as $path )
+               $modules = array_merge( (array) get_plugins( $path ), $modules );

            $this->_module_cache = array();