maxima-5.11.0-r2 ("~x86") depends on gcl lisp implementation, so gcl is installed. But maxima has gcl useflag turned off by default.
Steps to Reproduce:
1. echo "sci-mathematics/maxima ~x86" >> /etc/portage/package.keywords
2. euse --prune gcl
3. emerge --pretend --verbose maxima
gcl useflag is not selected
gcl useflag should be selected as dev-lisp/gcl is going to be installed as a lisp backend for maxima
Yeah, poke us back when IUSE defaults is allowed in gentoo-x86; until then, enable it yourself and move on.
*** Bug 189398 has been marked as a duplicate of this bug. ***
Sorry, I didn't know it's not an option. But is it possible at least to specify those flags in package.use.force? It's not immediate but will work when there is a new profile release.