dev-libs/libportal: prevent automagically building against gtk[X,wayland]

e.g. the upstream code checks whether GDK_WINDOWING_WAYLAND is defined
by the gtk headers, and if so will compile against the wayland symbols
it provides. This means that libportal built on a system with
gtk+[-wayland] will be compatible with anything, but when built on a
system with gtk+[wayland], requires that at runtime.

This cannot be expressed with USE flags.

We could bind tightly to whether gtk was built with wayland (and X), and
in the process, arbitrarily restrict libportal[-wayland] to only build
and install on a system with gtk+[-wayland].

But we recently added a hack to gtk itself which allows hiding the
automagic macros entirely. Inject this via append-cflags if the USE
flags aren't set, to simulate building on a system with more minimal gtk
packages.

Signed-off-by: Eli Schwartz <eschwartz93@gmail.com>
Signed-off-by: Eli Schwartz <eschwartz@gentoo.org>

dev-libs/libportal/libportal-0.7.1-r1.ebuild

@@ -0,0 +1,113 @@
+# Copyright 2022-2024 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=8
+
+PYTHON_COMPAT=( python3_{10..12} )
+inherit flag-o-matic meson python-any-r1 vala virtualx
+
+DESCRIPTION="Flatpak portal library"
+HOMEPAGE="https://github.com/flatpak/libportal"
+SRC_URI="https://github.com/flatpak/libportal/releases/download/${PV}/${P}.tar.xz"
+
+LICENSE="LGPL-3"
+SLOT="0/1-1-1-1" # soname of libportal{,-gtk3,-gtk4,-qt5}.so
+KEYWORDS="~alpha ~amd64 ~arm ~arm64 ~ia64 ~loong ~ppc ~ppc64 ~riscv ~sparc ~x86"
+IUSE="gtk gtk-doc +introspection qt5 test +vala wayland X"
+RESTRICT="!test? ( test )"
+REQUIRED_USE="
+	gtk-doc? ( introspection )
+	vala? ( introspection )
+"
+
+RDEPEND="
+	>=dev-libs/glib-2.58:2
+	introspection? ( dev-libs/gobject-introspection:= )
+	gtk? (
+		>=x11-libs/gtk+-3.24.41-r1:3[X?,wayland?]
+		>=gui-libs/gtk-4.12.5-r2:4[X?,wayland?]
+	)
+	qt5? (
+		dev-qt/qtcore:=
+		dev-qt/qtgui:=
+		dev-qt/qtx11extras:=
+		dev-qt/qtwidgets:=
+	)
+"
+DEPEND="${RDEPEND}
+	qt5? (
+		test? ( dev-qt/qttest:= )
+	)
+"
+BDEPEND="
+	dev-util/glib-utils
+	virtual/pkgconfig
+	gtk-doc? ( dev-util/gi-docgen )
+	qt5? (
+		test? ( dev-qt/linguist-tools )
+	)
+	test? (
+		${PYTHON_DEPS}
+		$(python_gen_any_dep '
+			dev-python/pytest[${PYTHON_USEDEP}]
+			dev-python/dbus-python[${PYTHON_USEDEP}]
+			dev-python/python-dbusmock[${PYTHON_USEDEP}]
+		')
+	)
+	vala? ( $(vala_depend) )
+"
+
+python_check_deps() {
+	python_has_version \
+		"dev-python/pytest[${PYTHON_USEDEP}]" \
+		"dev-python/dbus-python[${PYTHON_USEDEP}]" \
+		"dev-python/python-dbusmock[${PYTHON_USEDEP}]"
+}
+
+pkg_setup() {
+	if use test; then
+		python-any-r1_pkg_setup
+	fi
+}
+
+src_prepare() {
+	default
+	vala_setup
+}
+
+src_configure() {
+	# defang automagic dependencies
+	use wayland || append-cflags -DGENTOO_GTK_HIDE_WAYLAND
+	use X || append-cflags -DGENTOO_GTK_HIDE_X11
+
+	local emesonargs=(
+		$(meson_feature gtk backend-gtk3)
+		$(meson_feature gtk backend-gtk4)
+		$(meson_feature qt5 backend-qt5)
+		-Dportal-tests=false
+		$(meson_use introspection)
+		$(meson_use vala vapi)
+		$(meson_use gtk-doc docs)
+		$(meson_use test tests)
+	)
+	meson_src_configure
+}
+
+src_test() {
+	# Tests only exist for Qt5
+	if use qt5; then
+		virtx meson_src_test
+	else
+		# run meson_src_test to notice if tests are added
+		meson_src_test
+	fi
+}
+
+src_install() {
+	meson_src_install
+
+	if use gtk-doc; then
+		mkdir -p "${ED}"/usr/share/gtk-doc/html/ || die
+		mv "${ED}"/usr/share/doc/${PN}-1 "${ED}"/usr/share/gtk-doc/html/ || die
+	fi
+}

profiles/features/big-endian/package.use.mask

@@ -45,6 +45,7 @@ gui-libs/gtk wayland
 gnome-base/gnome-control-center wayland
 sys-apps/xdg-desktop-portal-gnome wayland
 net-libs/webkit-gtk:6 wayland
+dev-libs/libportal wayland
 
 # matoro <matoro_gentoo@matoro.tk> (2023-04-10)
 # media-libs/libldac casualties (#80238)