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/qthelp/qthelp-5.15.17.ebuild

@@ -0,0 +1,30 @@
+# Copyright 1999-2025 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=8
+
+if [[ ${PV} != *9999* ]]; then
+	QT5_KDEPATCHSET_REV=1
+	KEYWORDS="~amd64 ~arm ~arm64 ~hppa ~loong ~ppc ~ppc64 ~riscv ~x86"
+fi
+
+QT5_MODULE="qttools"
+inherit qt5-build
+
+DESCRIPTION="Qt5 module for integrating online documentation into applications"
+
+IUSE=""
+
+DEPEND="
+	=dev-qt/qtcore-${QT5_PV}*:5=
+	=dev-qt/qtgui-${QT5_PV}*
+	=dev-qt/qtsql-${QT5_PV}*[sqlite]
+	=dev-qt/qtwidgets-${QT5_PV}*
+"
+RDEPEND="${DEPEND}"
+
+QT5_TARGET_SUBDIRS=(
+	src/assistant/help
+	src/assistant/qcollectiongenerator
+	src/assistant/qhelpgenerator
+)