libinput: don't use weston_config when configuring input devices

Instead add callbacks to the drm and fbdev backends and pass that to
the input backens so that when a new device needs to be configured
that is called and the compositor can configure it.

Signed-off-by: Giulio Camuffo <giuliocamuffo@gmail.com>
Reviewed-by: Quentin Glidic <sardemff7+git@sardemff7.net>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
diff --git a/Makefile.am b/Makefile.am
index 1b32300..fd10c13 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -65,7 +65,8 @@
 weston_CPPFLAGS = $(AM_CPPFLAGS) -DIN_WESTON
 weston_CFLAGS = $(AM_CFLAGS) $(COMPOSITOR_CFLAGS) $(LIBUNWIND_CFLAGS)
 weston_LDADD = $(COMPOSITOR_LIBS) $(LIBUNWIND_LIBS) \
-	$(DLOPEN_LIBS) -lm $(CLOCK_GETTIME_LIBS) libshared.la
+	$(DLOPEN_LIBS) -lm $(CLOCK_GETTIME_LIBS) \
+	$(LIBINPUT_BACKEND_LIBS) libshared.la
 
 weston_SOURCES =					\
 	src/git-version.h				\