The doc-install function currently is designed to either use default paths when DOCS is unset, or use provided paths when DOCS is set. However, there's no explicit way of disabling doc-install completely.
I'd like to request that DOCS=() and DOCS='' explicitly disable installing docs. With the current definition, they would result in 'dodoc' with no parameters.
In EAPI 6:
*** Bug 480892 has been marked as a duplicate of this bug. ***