We are going to deprecate elisp-comp, see bug 235442, so elisp-compile should be used instead. Patch will follow.
Created attachment 163713 [details, diff] Proposed patch for cl-mcclim-0.9.2-r1.ebuild I think there's no need for a revbump since the installed files will be identical (except for a changed comment in the header of the .elc file). dev-lisp/mcclim in the gentoo-lisp overlay is also affected and the fix is almost identical. (Please not that the variable is called EMACS_SOURCES instead of ELISP_SOURCES there.)
Fixed it myself, with permission from hkbst.