contrib: fix SDL_image dependencies

contrib/src/SDL_image/rules.mak

@@ -18,6 +18,9 @@ SDL_image: SDL_image-$(SDL_IMAGE_VERSION).tar.gz .sum-SDL_image
 	$(APPLY) $(SRC)/SDL_image/SDL_image.patch
 	$(MOVE)
 
+DEPS_SDL_image = png $(DEPS_png) jpeg $(DEPS_jpeg) tiff $(DEPS_tiff) \
+	sdl $(DEPS_sdl)
+
 .SDL_image: SDL_image .png .jpeg .sdl
 	cd $< && $(HOSTVARS) ./configure $(HOSTCONF) --enable-tif --disable-sdltest
 	cd $< && $(MAKE) install

contrib/src/tiff/rules.mak

@@ -3,8 +3,6 @@
 TIFF_VERSION := 3.9.5
 TIFF_URL := ftp://ftp.remotesensing.org/libtiff/tiff-$(TIFF_VERSION).tar.gz
 
-PKGS += tiff
-
 $(TARBALLS)/tiff-$(TIFF_VERSION).tar.gz:
 	$(call download,$(TIFF_URL))