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/qdoc/qdoc-5.15.16.ebuild

@@ -0,0 +1,40 @@
+# Copyright 1999-2024 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=8
+
+if [[ ${PV} != *9999* ]]; then
+	QT5_KDEPATCHSET_REV=1
+	KEYWORDS="amd64 ~arm arm64 ~ppc64 ~riscv x86"
+fi
+
+QT5_MODULE="qttools"
+inherit qt5-build
+
+DESCRIPTION="Qt documentation generator"
+
+IUSE="qml"
+
+DEPEND="
+	=dev-qt/qtcore-${QT5_PV}*:5=
+	llvm-core/clang:=
+	qml? ( =dev-qt/qtdeclarative-${QT5_PV}* )
+"
+RDEPEND="${DEPEND}"
+
+QT5_TARGET_SUBDIRS=(
+	src/qdoc
+)
+
+src_prepare() {
+	qt_use_disable_mod qml qmldevtools-private \
+		src/qdoc/qdoc.pro
+
+	qt5-build_src_prepare
+}
+
+src_configure() {
+	# qt5_tools_configure() not enough here, needs another fix, bug 676948
+	qt5_configure_oos_quirk qtqdoc-config.pri src/qdoc
+	qt5-build_src_configure
+}