packagegroup-base: Add option to set zeroconf provider

avahi, systemd-resolved and mDNSResponder (in meta-networking) can all
provide Zeroconf services. Add a `ZEROCONF_DAEMON` option to select
which of these will provide service via packagegroup-base-zeroconf.

Signed-off-by: Alex Kiernan <alex.kiernan@gmail.com>
Signed-off-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

Author: akiernan

meta/recipes-core/packagegroups/packagegroup-base.bb

@@ -312,11 +312,14 @@ RDEPENDS:packagegroup-base-nfs = "\
 RRECOMMENDS:packagegroup-base-nfs = "\
     kernel-module-nfs "
 
+# Choose 'avahi-daemon', 'mdns' or 'systemd-resolved' as zeroconf-daemon
+ZEROCONF_DAEMON ??= "${@bb.utils.contains('DISTRO_FEATURES', 'systemd-resolved', 'systemd-resolved', 'avahi-daemon', d)}"
 SUMMARY:packagegroup-base-zeroconf = "Zeroconf support"
 RDEPENDS:packagegroup-base-zeroconf = "\
-    avahi-daemon"
+    ${@ '' if d.getVar('ZEROCONF_DAEMON') == 'systemd-resolved' else d.getVar('ZEROCONF_DAEMON')} \
+    "
 RDEPENDS:packagegroup-base-zeroconf:append:libc-glibc = "\
-    libnss-mdns \
+    ${@ {'mdns':'mdns-libnss-mdns','avahi-daemon':'avahi-libnss-mdns','systemd-resolved':''}[d.getVar('ZEROCONF_DAEMON')]} \
     "
 
 SUMMARY:packagegroup-base-ipv6 = "IPv6 support"