media-libs/zxing-cpp: Disable examples build, add IUSE="test"

Closes: https://bugs.gentoo.org/747841
Package-Manager: Portage-3.0.8, Repoman-3.0.1
Signed-off-by: Andreas Sturmlechner <asturm@gentoo.org>

media-libs/zxing-cpp/zxing-cpp-1.1.1.ebuild

@@ -12,4 +12,14 @@ SRC_URI="https://github.com/nu-book/${PN}/archive/v${PV}.tar.gz -> ${P}.tar.gz"
 LICENSE="Apache-2.0"
 SLOT="0"
 KEYWORDS="~amd64 ~arm64 ~ppc64 ~x86"
-IUSE=""
+IUSE="test"
+
+RESTRICT="!test? ( test )"
+
+src_configure() {
+	local mycmakeargs=(
+		-DBUILD_EXAMPLES=OFF # nothing is installed
+		-DBUILD_BLACKBOX_TESTS=$(usex test)
+	)
+	cmake_src_configure
+}