failure to find non-registered files installed in sites/all

If one installs components which do not have a registered path in the system table in the database, then drupal_get_filename() will not find them.

example: install smarty engine in 'sites/all/themes/engines' and it will fail because it cannot find it's own library.

fix: add the sites/all paths into the path search loop for drupal_get_filename()

 ** root@ethel ** /usr/local/www/drupal6 ** Mon Dec 08 16:17:00
# diff -c includes/bootstrap.inc~ includes/bootstrap.inc
*** includes/bootstrap.inc~	Sat Oct 25 11:05:16 2008
--- includes/bootstrap.inc	Mon Dec  8 16:15:23 2008
***************
*** 413,420 ****
      $dir = (($type == 'theme_engine') ? 'themes/engines' : "${type}s");
      $file = (($type == 'theme_engine') ? "$name.engine" : "$name.$type");
  
!     foreach (array("$config/$dir/$file", "$config/$dir/$name/$file", "$dir/$file", "$dir/$name/$file") as $file) {
!       if (file_exists($file)) {
          $files[$type][$name] = $file;
          break;
        }
--- 413,427 ----
      $dir = (($type == 'theme_engine') ? 'themes/engines' : "${type}s");
      $file = (($type == 'theme_engine') ? "$name.engine" : "$name.$type");
  
!     foreach (array(
!                "$config/$dir/$file",
!                "$config/$dir/$name/$file",
!                "sites/all/$dir/$file",
!                "sites/all/$dir/$name/$file",
!                "$dir/$file",
!                "$dir/$name/$file",
!                ) as $file) {
!       if (file_exists('./'. $file)) {
          $files[$type][$name] = $file;
          break;
        }

discussion: I'm new to Drupal; so I don't have the history to know whether there is a larger reason why the sites/all path is excluded. I am also worried that hard coding the sites/all path is poor practice; but I don't know where that might be stored as a constant or variable.

versions:

os

FreeBSD FreeBSD 7.0-RELEASE-p3

apache

2.2.9 FreeBSD patch level 5

php

5.2.6 FreeBSD patch level 2

drupal

6.6 (but the same problem appears in the CVS DRUPAL-6 version of bootstrap.inc)

drupal root: /usr/local/www/drupal6