games-emulation/dosbox-staging: add missing flag for libslirp support

This is used in this new version for Ethernet emulation

Closes: https://bugs.gentoo.org/830229
Package-Manager: Portage-3.0.30, Repoman-3.0.3
Signed-off-by: Bernard Cafarelli <voyageur@gentoo.org>

games-emulation/dosbox-staging/dosbox-staging-0.78.0.ebuild

@@ -11,7 +11,7 @@ SRC_URI="https://github.com/dosbox-staging/dosbox-staging/archive/v${PV}.tar.gz
 LICENSE="GPL-2+"
 SLOT="0"
 KEYWORDS="~amd64 ~ppc ~ppc64 ~x86"
-IUSE="+alsa debug dynrec +fluidsynth mt-32 network opengl test"
+IUSE="+alsa debug dynrec +fluidsynth mt-32 network opengl slirp test"
 
 RESTRICT="!test? ( test )"
 
@@ -24,6 +24,7 @@ RDEPEND="alsa? ( media-libs/alsa-lib )
 	mt-32? ( media-libs/munt-mt32emu )
 	network? ( media-libs/sdl2-net )
 	opengl? ( virtual/opengl )
+	slirp? ( net-libs/libslirp )
 	media-libs/libpng:0=
 	media-libs/libsdl2[joystick,opengl?,video,X]
 	media-libs/opusfile
@@ -58,6 +59,7 @@ src_configure() {
 		$(meson_use mt-32 use_mt32emu)
 		$(meson_use network use_sdl2_net)
 		$(meson_use opengl use_opengl)
+		$(meson_use slirp use_slirp)
 		$(meson_feature test unit_tests)
 	)
 	meson_src_configure

games-emulation/dosbox-staging/metadata.xml

@@ -11,6 +11,7 @@
 		<flag name="mt-32">use <pkg>media-libs/munt-mt32emu</pkg> for MT-32 emulation</flag>
 		<flag name="network">Enable networking features (modem, ipx)</flag>
 		<flag name="opus">Support compressed audio tracks (.opus) used with CDROM images</flag>
+		<flag name="slirp">Enable Ethernet emulation using <pkg>net-libs/libslirp</pkg></flag>
 	</use>
 	<upstream>
 		<remote-id type="github">dosbox-staging/dosbox-staging</remote-id>