Please add "!bindist? ( bindist )" to the ebuild's RESTRICT, in order to restrict binary distribution with USE=-bindist. See the tracker bug 541408 for further explanation.
Please hold on, because we might go for a different solution. See bug 541588 for discussion.
Following up to the discussion in gentoo-dev, please add the following to the ebuild's RESTRICT variable: "firebird? ( bindist )" and remove the bindist flag from IUSE, REQUIRED_USE, and RDEPEND.
Fixed, thanks for standardizing this. + 07 Mar 2015; Alexandre Rostovtsev <tetromino@gentoo.org> libgda-5.2.2.ebuild, + metadata.xml: + bindist is now a RESTRICT flag, not a USE flag (bug #541456, thanks to Ulrich + Müller).