This is a spin-off from bug #228885 comment #38, with a very limited scope: Please adjust the elog messages of shared-mime-info to avoid confusion, i.e. 1. only refer to /usr/local/share/mime if such a directory exists and 2. indicate that missing dirs indicate no need for action. Attachment #184413 [details, diff] takes care of both these issues, and still applies to current shared-mime-info-0.71.ebuild. I'll re-attach the patch here.
Created attachment 223597 [details, diff] Proposed ebuild improvement
I've added something like this to 0.80, but commented the whole thing out in the ebuild because AFAIK the format hasn't changed in a while... If it does, your change should be there.