I've created a new ebuild for the recently released mono-1.1.9 version. Added a new Dependency (sys-devel/bc, required for make to work). There's the new ebuild (based on the 1.1.8 one) attached to this bugreport. Tested in local with success! Reproducible: Always Steps to Reproduce:
Created attachment 68364 [details] mono 1.1.9 ebuild
Version bumped in portage, based off my work. Thanks for the bug though. Marking FIXED.