Revert "dev-libs/mtxclient: Remove old ebuild."

Turns out <=net-im/nheko-0.8.1 doesn't work with
>=dev-libs/mtxclient-0.5.0.

This reverts commit 760f3c9463.

Signed-off-by: Ronny (tastytea) Gutbrod <gentoo@tastytea.de>

dev-libs/mtxclient/mtxclient-0.4.1.ebuild

@@ -0,0 +1,44 @@
+# Copyright 2020-2021 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=7
+
+inherit cmake
+
+DESCRIPTION="Client API library for Matrix, built on top of Boost.Asio"
+HOMEPAGE="https://github.com/Nheko-Reborn/mtxclient"
+SRC_URI="https://github.com/Nheko-Reborn/${PN}/archive/v${PV}.tar.gz -> ${P}.tar.gz"
+
+LICENSE="MIT"
+SLOT="0"
+KEYWORDS="~amd64"
+
+IUSE="test"
+RESTRICT="!test? ( test )"
+
+RDEPEND="
+	>=dev-libs/boost-1.70.0
+	dev-libs/olm
+	>=dev-libs/openssl-1.1.0
+	dev-cpp/nlohmann_json
+"
+DEPEND="
+	${RDEPEND}
+	dev-libs/spdlog
+	test? ( dev-cpp/gtest )
+"
+
+# remove_failing_tests depends on remove_network_tests.
+PATCHES=(
+	"${FILESDIR}/0.3.0_remove_network_tests.patch"
+	"${FILESDIR}/0.3.0_remove_failing_tests.patch"
+)
+
+src_configure() {
+	local -a mycmakeargs=(
+		-DBUILD_LIB_TESTS="$(usex test)"
+		-DBUILD_LIB_EXAMPLES=OFF
+	)
+
+	cmake_src_configure
+}