Same as #40953 and #40347, but affects qmamecat. Here's the patch, copied from xxdiff.
Created attachment 25289 [details, diff] Ebuild patch
perhaps better way is to figure out a way of inherit-ing kde eclass and addwrite to it
Created attachment 25350 [details, diff] Ebuild patch v2 This patch acknowledges SpanKY's suggestion. Should work for every ebuild with the same problem. The "none" argument to kde_src_compile prevents it to default to "all" and does just nothing! :)
Applied to the ebuild. Thanks for the patch and bug report.