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/qtimageformats/qtimageformats-5.15.17.ebuild

@@ -0,0 +1,32 @@
+# Copyright 1999-2025 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=8
+
+if [[ ${PV} != *9999* ]]; then
+	QT5_KDEPATCHSET_REV=1
+	KEYWORDS="~amd64 ~arm ~arm64 ~hppa ~loong ~ppc64 ~riscv ~x86"
+fi
+
+inherit qt5-build
+
+DESCRIPTION="Additional format plugins for the Qt image I/O system"
+
+IUSE="mng"
+
+DEPEND="
+	=dev-qt/qtcore-${QT5_PV}*
+	=dev-qt/qtgui-${QT5_PV}*
+	media-libs/libwebp:=
+	media-libs/tiff:=
+	mng? ( media-libs/libmng:= )
+"
+RDEPEND="${DEPEND}"
+
+src_configure() {
+	sed -e 's/qtConfig(jasper)/false:/' \
+		-i src/plugins/imageformats/imageformats.pro || die
+	qt_use_disable_config mng mng src/plugins/imageformats/imageformats.pro
+
+	qt5-build_src_configure
+}