libweston: Properly namespace modules entrypoint

Use different functions so we cannot load a libweston common module in
weston directly or the other way around.

Signed-off-by: Quentin Glidic <sardemff7+git@sardemff7.net>
Reviewed-by: Daniel Stone <daniels@collabora.com>
diff --git a/libweston/compositor.h b/libweston/compositor.h
index 1e57b3f..b049c98 100644
--- a/libweston/compositor.h
+++ b/libweston/compositor.h
@@ -1818,8 +1818,7 @@
 weston_backend_init(struct weston_compositor *c,
 		    struct weston_backend_config *config_base);
 int
-module_init(struct weston_compositor *compositor,
-	    int *argc, char *argv[]);
+weston_module_init(struct weston_compositor *compositor);
 
 void
 weston_transformed_coord(int width, int height,