I don't see a setting that allows for absolute URLs, and the code for this may be in different locations (different web parts mainly).
Two options then:
If the urls must be proper from the server (server side logic), what i would do is use the CMS Modules to create a setting (say "use Absolute") and a setting for the absolute domain name, and then wherever you need the absolute url to appear clone and modify that tool to use the specified domain name before hand. Perhaps putting the logic in a function that handles both the "Should i use the absolute url or not" and what one it uses, so you just call that function beforehand.
Something like $("*[href]:not([href^='http'])").attr("href", "http://mydomain.com/"+$(this).attr("href"));