package/wireplumber: fix package by making the dbus dependency optional

The wireplumber currently as "dbus" in its DEPENDENCIES, but it does
not select/depend on it at the Kconfig level. A simple configuration
such as:

BR2_PACKAGE_LUA=y
BR2_PACKAGE_PIPEWIRE=y
BR2_PACKAGE_WIREPLUMBER=y

Therefore fails to build with:

Makefile:576: *** dbus is in the dependency chain of wireplumber that has added it to its _DEPENDENCIES variable without selecting it or depending on it from Config.in.  Stop.

Since dbus is actually an optional dependency of wireplumber, this
commit fixes the issue by really handling it as an optional
dependency.

Fixes: c9a3c10417aadce9ee4922e30235776409ce8eb3 ("package/wireplumber: new package")
Signed-off-by: Théo Lebrun <theo.lebrun@bootlin.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/wireplumber/wireplumber.mk

@@ -9,13 +9,17 @@ WIREPLUMBER_SOURCE = wireplumber-$(WIREPLUMBER_VERSION).tar.bz2
 WIREPLUMBER_SITE = https://gitlab.freedesktop.org/pipewire/wireplumber/-/archive/$(WIREPLUMBER_VERSION)
 WIREPLUMBER_LICENSE = MIT
 WIREPLUMBER_LICENSE_FILES = LICENSE
-WIREPLUMBER_DEPENDENCIES = host-pkgconf dbus pipewire libglib2 lua
+WIREPLUMBER_DEPENDENCIES = host-pkgconf pipewire libglib2 lua
 
 WIREPLUMBER_CONF_OPTS = \
 	-Ddoc=disabled \
 	-Dsystem-lua=true \
 	-Dsystem-lua-version=
 
+ifeq ($(BR2_PACKAGE_DBUS),y)
+WIREPLUMBER_DEPENDENCIES += dbus
+endif
+
 ifeq ($(BR2_PACKAGE_GOBJECT_INTROSPECTION),y)
 WIREPLUMBER_DEPENDENCIES += host-doxygen host-python-lxml gobject-introspection
 WIREPLUMBER_CONF_OPTS += -Dintrospection=enabled