define DRUPAL_CONFDIR for use in conf_path() and drupal_system_listing().

Yes, please!
This would be _particularly_ useful for running out of a read-only drupal installation on, for example, a shared host.

Example hypothetical:
Shared Server 'shserv92'.
Drupal installed in /usr/web/cms/drupal/7.
Shared Hosting Subscriber 'shuser4231234'.
Per-user web root ~shuser4231234/public_html.
~shuser4231234/public_html/index.php specifies:
…

    define('DRUPAL_ROOT', '/usr/web/cms/drupal/7');                                                                                  
    require(DRUPAL_ROOT . '/index.php');

BUT, then Drupal would try to read it's configuration from DRUPAL_ROOT/sites!

Add to ~shuser4231234/public_html/index.php:

    define('DRUPAL_CONFDIR', $_SERVER["DOCUMENT_ROOT"] . '/sites'); // ...or define conf_path_alter()…

Then, Problem solved. This is more than multi-site, this is multi-conf.

For now, conf_path() needs to be hacked.

:-/

Upon further investigation, it appears that drupal_system_listing() would also need modification, since it hard-codes 'sites/all' and 'profiles'.

Here's my attempt at a patch.

Summary: (1) Change 'sites/all' to DRUPAL_CONFDIR . '/all', (2) change "profiles" to DRUPAL_ROOT . "/profiles".

There are two things which are missing/incomplete: (1) comments, (2) the location of the define() call.

Right now, I've placed the same new call to define() once _each_ in common.inc and bootstrap.inc, _inside_ conf_path() and drupal_system_listing(). This is certainly the wrong place. I think it should just go near the top of bootstrap.inc somewhere.

JP

Slightly updated patch, now including install.core.inc. No other changes.

I'm not sure what that MySQL failure means…
¿install.core.inc -> install_check_requirements() -> $default_settings_file needs to be a relative path?

¿Or, drupal_system_listing()'s $searchdir needs to be a relative path?

So, I've figured out that file_scan_directory() returns paths which are expected to be relative to the web-server's DOCROOT. I'm not sure what to do about that. Perhaps strip the first several path components off (so that DRUPAL_CONFDIR is reduced to a single path component) _after_ the search completes (i.e. drupal_system_listing(), after file_scan_directory() returns), on the assumption that DRUPAL_CONFDIR is DOCROOT/something. That seems like a lot of work. Considering this is a search function, maybe the additional path-munging won't be significant.

Remember, I'm not just trying to rename 'sites'. I'm trying to move it to a different location on disk.

Also, updated patch removing changes to install.core.inc: default.settings.php _should_ be pulled from inside DRUPAL_ROOT, not from DRUPAL_CONFDIR.