just realised that there's this awesome overlay containing the ebuild (and others): https://bitbucket.org/hasufell/hasufell-overlay.git

games-strategy/0ad/0ad-99999.ebuild

@@ -1,128 +0,0 @@
-# Copyright 1999-2012 Gentoo Foundation
-# Distributed under the terms of the GNU General Public License v2
-# $Header: $
-
-EAPI=3
-
-WX_GTK_VER="2.8"
-
-inherit eutils subversion wxwidgets games
-
-MY_PV="r${PV%_*}-alpha"
-MY_P=${PN}-${MY_PV}
-
-DESCRIPTION="A free, real-time strategy game"
-HOMEPAGE="http://wildfiregames.com/0ad/"
-ESVN_REPO_URI="http://svn.wildfiregames.com/public/ps/trunk"
-
-LICENSE="GPL-2 LGPL-2.1 MIT CCPL-Attribution-ShareAlike-3.0 as-is"
-SLOT="0"
-KEYWORDS=""
-IUSE="+audio +editor fam +nvtt +pch test"
-
-RDEPEND="
-	>=dev-lang/spidermonkey-1.8.5
-	dev-libs/boost
-	dev-libs/libxml2
-	!games-strategy/0ad-data
-	media-libs/libpng:0
-	media-libs/libsdl[X,audio?,opengl,video]
-	net-libs/enet:1.3
-	net-misc/curl
-	sys-libs/zlib
-	virtual/jpeg
-	virtual/opengl
-	audio? ( media-libs/libogg
-		media-libs/libvorbis
-		media-libs/openal )
-	editor? ( x11-libs/wxGTK:2.8[X] )
-	fam? ( virtual/fam )
-	nvtt? ( dev-util/nvidia-texture-tools )
-	"
-DEPEND="${RDEPEND}
-	dev-util/pkgconfig
-	test? ( dev-lang/perl )"
-
-S=${WORKDIR}/trunk
-
-pkg_setup() {
-	games_pkg_setup
-
-	if ! use pch ; then
-		eerror "pch useflag is potentially broken"
-		eerror "see http://trac.wildfiregames.com/ticket/1313"
-	fi
-}
-
-src_unpack() {
-	subversion_src_unpack
-}
-
-src_prepare() {
-	# respect flags for 3rd party fcollada
-	epatch "${FILESDIR}"/11339_alpha9-fcollada-makefile.patch
-}
-
-src_configure() {
-	cd build/workspaces || die
-
-	# custom configure script
-	local myconf
-	use nvtt || myconf="--without-nvtt"
-	use fam || myconf="${myconf} --without-fam"
-	use pch || myconf="${myconf} --without-pch"
-	use test || myconf="${myconf} --without-tests"
-	use audio || myconf="${myconf} --without-audio"
-
-	# don't use bundled sources
-	./update-workspaces.sh \
-		--with-system-nvtt \
-		--with-system-enet \
-		--with-system-mozjs185 \
-		$(use_enable editor atlas) \
-		--bindir="${GAMES_BINDIR}" \
-		--libdir="$(games_get_libdir)"/${PN} \
-		--datadir="${GAMES_DATADIR}"/${PN} \
-		${myconf} || die
-}
-
-src_compile() {
-	cd build/workspaces/gcc || die
-
-	emake CONFIG=Release verbose=1 || die
-}
-
-src_test() {
-	cd binaries/system || die
-
-	if use nvtt ; then
-		./test || die "test phase failed"
-	else
-		ewarn "Skipping tests because USE nvtt is disabled"
-	fi
-}
-
-src_install() {
-	# data
-	insinto "${GAMES_DATADIR}"/${PN}
-	doins -r binaries/data/* || die
-
-	# bin
-	dogamesbin binaries/system/pyrogenesis || die
-
-	# libs
-	exeinto "$(games_get_libdir)"/${PN}
-	doexe binaries/system/libCollada.so || die
-	if use editor ; then
-		doexe binaries/system/libAtlasUI.so || die
-	fi
-
-	# other
-	dodoc binaries/system/readme.txt || die
-	doicon build/resources/${PN}.png || die
-	games_make_wrapper ${PN} "${GAMES_BINDIR}/pyrogenesis"
-	make_desktop_entry ${PN} ${PN} ${PN}
-
-	# permissions
-	prepgamesdirs
-}

games-strategy/0ad/Manifest

@@ -1 +0,0 @@
-EBUILD 0ad-99999.ebuild 2725 SHA256 14d9fa3605f6b36229a7f3de5a8d772feb750d313a2971f7da97f35e06356b34 SHA512 aad5b87e21813bf0e4b2629c40cf43585272d2d6a44fe298818d1b2276b2fe149b76f2f1cc476b58e6030f8ff73ebcecd1fb556e66bdf87608b99a4291c17e3c WHIRLPOOL 155d29724f1fc015ca9733720f2c63bca72d348b43dbe7a1e30b35e29dfbf5c8d5f6e0f29638c6161c7b93adcdabc25ff338a3b2dcd3ca122f64af0d99e83e2c