Can't use Text module in Install Profile

At the top of the text module, this code fails when run from an install profile:

include_once('./'. drupal_get_path('module', 'content') .'/content.module');

It should be this (drupal_get_path doesn't work at install time):

include_once(dirname(__FILE__) . '/../../content.module');

This change has already been made in content.module, presumably for the same reason. It needs to be done everywhere else too.