Firstly, thanks for reporting the issue, but there isn't a generic fix that I can think of - let me explain.
From what I understand, $base_url is often used when using multi-side configurations, so when drupal creates links to resources (files / images) is prepends the base_url to the resouce. If we would integrate your solution we would need to specify a base_url for the default site (e.g. http://localhost), but that would break existing code.
One solution does come to mind though, and that is to create an array in the cron script which stores each cron url it calls, and not call a url that has already been called. Though, this wouldn't really solve your specific issue.
Bottom line, I'd recommend either not creating a site folder if it's not being used, or tweak the cron script (it's in etc for that reason). I know this isn't a very good answer/solution, but the only one I currently can offer.
I'm still open to other solutions if you'd like to propose any.
BTW, the cron script is from the upstream packaging (debian), so if we do come up with a reasonable solution, I'd recommend submitting a patch upstream for inclusion in the official package.
Firstly, thanks for reporting the issue...
Firstly, thanks for reporting the issue, but there isn't a generic fix that I can think of - let me explain.
From what I understand, $base_url is often used when using multi-side configurations, so when drupal creates links to resources (files / images) is prepends the base_url to the resouce. If we would integrate your solution we would need to specify a base_url for the default site (e.g. http://localhost), but that would break existing code.
One solution does come to mind though, and that is to create an array in the cron script which stores each cron url it calls, and not call a url that has already been called. Though, this wouldn't really solve your specific issue.
Bottom line, I'd recommend either not creating a site folder if it's not being used, or tweak the cron script (it's in etc for that reason). I know this isn't a very good answer/solution, but the only one I currently can offer.
I'm still open to other solutions if you'd like to propose any.
BTW, the cron script is from the upstream packaging (debian), so if we do come up with a reasonable solution, I'd recommend submitting a patch upstream for inclusion in the official package.