sci-mathematics/clasp: use system catch

Closes: https://bugs.gentoo.org/842327
Signed-off-by: Alessandro Barbieri <lssndrbarbieri@gmail.com>

sci-mathematics/clasp/clasp-3.3.7.ebuild

@@ -18,7 +18,10 @@ KEYWORDS="~amd64"
 IUSE="examples test +threads +tools"
 
 RDEPEND="sci-libs/libpotassco:="
-DEPEND="${RDEPEND}"
+DEPEND="
+	${RDEPEND}
+	test? ( dev-cpp/catch:0 )
+"
 
 RESTRICT="!test? ( test )"
 PATCHES=(
@@ -26,6 +29,11 @@ PATCHES=(
 	"${FILESDIR}/${P}-libclasp_app.patch"
 )
 
+src_prepare() {
+	rm tests/catch.hpp || die
+	cmake_src_prepare
+}
+
 src_configure() {
 	local mycmakeargs=(
 		-DCLASP_BUILD_APP=$(usex tools)