build: install the D-Bus introspection data

This would make it easier to develop against NetworkManager D-Bus API.

Makefile.am

@@ -295,11 +295,9 @@ introspection/%.h: introspection/%.c
 docs/api/dbus-%.xml: introspection/%.c
 	$()
 
-BUILT_SOURCES += \
+dbusinterfacesdir = $(datadir)/dbus-1/interfaces
-	$(introspection_sources) \
-	$(DBUS_INTERFACE_DOCS)
 
-EXTRA_DIST += \
+dbusinterfaces_DATA = \
 	introspection/org.freedesktop.NetworkManager.AccessPoint.xml \
 	introspection/org.freedesktop.NetworkManager.Connection.Active.xml \
 	introspection/org.freedesktop.NetworkManager.AgentManager.xml \
@@ -337,6 +335,13 @@ EXTRA_DIST += \
 	introspection/org.freedesktop.NetworkManager.VPN.Plugin.xml \
 	introspection/org.freedesktop.NetworkManager.WiMax.Nsp.xml
 
+BUILT_SOURCES += \
+	$(introspection_sources) \
+	$(DBUS_INTERFACE_DOCS)
+
+EXTRA_DIST += \
+	$(dbusinterfaces_DATA)
+
 ###############################################################################
 
 libnm_core_lib_h_pub_real = \

contrib/fedora/rpm/NetworkManager.spec

@@ -639,6 +639,7 @@ fi
 %{_datadir}/gtk-doc/html/libnm/*
 %{_datadir}/vala/vapi/libnm.deps
 %{_datadir}/vala/vapi/libnm.vapi
+%{_datadir}/dbus-1/interfaces/*.xml
 
 %files config-connectivity-fedora
 %dir %{nmlibdir}