saltstack/salt — pull request #958 by blast-hardcheese (2012-03-19 00:27:14+00:00)
Title: Adding some logic to handle virtual packages

If aptitude is installed, it is used to check whether a virtual package
has been satisfied.

Aptitude awesomeness found here:
http://unix.stackexchange.com/questions/14295/aptitude-what-is-the-filter-for-virtual-packages-that-has-been-provided

(Take two on this pull request)