portage.const: restore two dropped features

The script used to clean this up accidentally dropped two features.

Reported-by: Sebastian Luther <SebastianLuther@gmx.de>
docompress: add --limit support with newer EAPIs

We added support for not compressing files below a certain size (since the
speed/size/etc... tradeoffs didn't make sense), but it was only for man
pages and old EAPI's.

Add the logic to the newer EAPIs and apply to all compressed paths.

URL: http://bugs.gentoo.org/169260