Drupal 7.43 dies with a fatal error if drupal_goto() is called very early in the bootstrap

I ran into an issue with Drupal 7.43 on a site that has some code which can call drupal_goto() very early in the bootstrap (by manually including the includes/common.inc file first). drupal_goto() now calls current_path(), which isn't available yet, leading to a fatal error.

The site can fix this itself (and maybe should given how unusual of a case it is) but it also might be reasonable for core to just check $_GET['q'] here since that's what some other core functions already do if they think they might be called very early in the bootstrap.