avahi: enable glib / gtk support if available

package/avahi/avahi.mk

@@ -72,11 +72,8 @@ AVAHI_CONF_ENV = ac_cv_func_strtod=yes \
 		avahi_cv_sys_cxx_works=yes
 
 AVAHI_CONF_OPT = --localstatedir=/var \
-		--disable-glib \
-		--disable-gobject \
 		--disable-qt3 \
 		--disable-qt4 \
-		--disable-gtk \
 		--disable-gdbm \
 		--disable-python-dbus \
 		--disable-pygtk \
@@ -112,6 +109,18 @@ else
 AVAHI_CONF_OPT += --disable-dbus
 endif
 
+ifeq ($(BR2_PACKAGE_LIBGLIB2),y)
+AVAHI_DEPENDENCIES += libglib2
+else
+AVAHI_CONF_OPT += --disable-glib --disable-gobject
+endif
+
+ifeq ($(BR2_PACKAGE_LIBGTK2),y)
+AVAHI_DEPENDENCIES += libgtk2
+else
+AVAHI_CONF_OPT += --disable-gtk
+endif
+
 ifeq ($(BR2_PACKAGE_PYTHON),y)
 AVAHI_CONF_ENV += am_cv_pathless_PYTHON=python \
 		am_cv_path_PYTHON=$(PYTHON_TARGET_BINARY) \