package/gensio: use mdns option

mdns option is available since version 2.4.0 and
https://github.com/cminyard/gensio/commit/0b56fdd8205dff8f2343d1672e58b6583772f897

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/gensio/gensio.mk

@@ -9,7 +9,6 @@ GENSIO_SITE = http://downloads.sourceforge.net/project/ser2net/ser2net
 GENSIO_LICENSE = LGPL-2.1+ (library), GPL-2.0+ (tools)
 GENSIO_LICENSE_FILES = COPYING.LIB COPYING
 GENSIO_INSTALL_STAGING = YES
-GENSIO_DEPENDENCIES = $(if $(BR2_PACKAGE_AVAHI_LIBAVAHI_CLIENT),avahi)
 GENSIO_CONF_OPTS = \
 	--without-swig \
 	--without-python
@@ -21,6 +20,13 @@ else
 GENSIO_CONF_OPTS += --without-alsa
 endif
 
+ifeq ($(BR2_PACKAGE_AVAHI_LIBAVAHI_CLIENT),y)
+GENSIO_DEPENDENCIES += avahi
+GENSIO_CONF_OPTS += --with-mdns
+else
+GENSIO_CONF_OPTS += --without-mdns
+endif
+
 ifeq ($(BR2_PACKAGE_LIBGLIB2),y)
 GENSIO_DEPENDENCIES += host-pkgconf libglib2
 GENSIO_CONF_OPTS += --with-glib