Use a subfolder for the contribs prebuilt...

Else, we'll go mad over the management of this huge folder.

contrib/src/main.mak

@@ -270,7 +270,7 @@ distclean: clean
 	$(RM) config.mak
 	unlink Makefile
 
-PREBUILT_URL=ftp://ftp.videolan.org/pub/videolan/contrib/vlc-contrib-$(HOST)-latest.tar.bz2
+PREBUILT_URL=ftp://ftp.videolan.org/pub/videolan/contrib/$(HOST)/vlc-contrib-$(HOST)-latest.tar.bz2
 
 vlc-contrib-$(HOST)-latest.tar.bz2:
 	$(call download,$(PREBUILT_URL))