Add dev-qt from an older version of the gentoo repo

Qt5 has been removed, we restore it since we still use it.

dev-qt/qtserialbus/qtserialbus-6.10.3.ebuild

@@ -0,0 +1,38 @@
+# Copyright 2024-2026 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=8
+
+inherit qt6-build
+
+DESCRIPTION="Qt module to access CAN, ModBus, and other industrial serial buses and protocols"
+
+if [[ ${QT6_BUILD_TYPE} == release ]]; then
+	KEYWORDS="amd64 x86"
+fi
+
+RDEPEND="
+	~dev-qt/qtbase-${PV}:6[network]
+	~dev-qt/qtserialport-${PV}:6
+"
+DEPEND="${RDEPEND}"
+
+CMAKE_SKIP_TESTS=(
+	# rarely fails randomly (perhaps related to -j)
+	tst_qcandbcfileparser
+)
+
+src_install() {
+	qt6-build_src_install
+
+	if use test; then
+		local delete=( # sigh
+			"${D}${QT6_LIBDIR}"/cmake/Qt6SerialBus/*TestCanBusPlugin*.cmake
+			"${D}${QT6_MKSPECSDIR}"/modules/qt_plugin_qttestcanbus.pri
+			"${D}${QT6_PLUGINDIR}"/canbus/libqttestcanbus.*
+			"${D}${QT6_PLUGINDIR}"/canbus/objects-*/
+		)
+		# using -f given not tracking which tests may be skipped or not
+		rm -rf -- "${delete[@]}" || die
+	fi
+}