rcmail module looking in wrong places for roundcubemail

rcmail module didn't work with roundcubemail installed to the root or into the module dir (sites/all/modules/rcmail). Looked in the log to find that rcmail is looking for it in modules/rcmail/roundcubemail. This is totally broken. As per core devs only core modules are "supposed to" be installed into modules/ so even as a default this is incorrect.

The problem occurs in the function rcmail_page() in this following line:

Hardcoding the installation path to a place where you're not even supposed to install the module is pretty incorrect. And since a location to which roundcubemail is supposed to be installed is never given in the install instructions (see my issue http://drupal.org/node/119449) this is even more confounding. No one who cannot read php code can even install this module unless they accomplish it by a combination of dumb luck and doing the "wrong" thing.

A patch that fixes this problem is attached. It uses the base_path() and drupal_get_path() functions to determine the actual path of where the module is installed. It does assume that roundcubemail is installed inside of the module directory. It would be better if it could also detect if it is installed in /roundcubemail but I didn't think it was strictly necessary so I didn't write it. It would be pretty easy, however.