Fix Makefile to put site in _build

Makefile

@@ -1,9 +1,23 @@
-mlem.gif: mlem_bg.gif
-	gifsicle -U mlem_bg.gif -o mlem_bg_u.gif
-	convert -transparent '#ff9bc7' mlem_bg_u.gif mlem_t.gif
-	gifsicle --disposal=previous mlem_t.gif -o mlem.gif
+FONTS  = $(shell find fonts -type f)
+CSS    = style.css
+PAGES  = index.html
+IMAGES = mlem.gif
+
+all: $(patsubst %,_build/%,$(FONTS) $(CSS) $(PAGES) $(IMAGES))
+
+_build/%: %
+	@echo $*
+	@mkdir -p $(dir $@)
+	@cp $< $@
+
+_build/%.gif: %_bg.gif
+	@echo $*.gif
+	@mkdir -p $(dir _build/%* _tmp/%*)
+	@gifsicle -U $*_bg.gif -o _tmp/$*_bg_u.gif
+	@convert -transparent '#ff9bc7' _tmp/$*_bg_u.gif _tmp/$*_t.gif
+	@gifsicle --disposal=previous _tmp/$*_t.gif -o _build/$*.gif
 
 clean:
-	$(RM) mlem_bg_u.gif mlem_t.gif mlem.gif
+	$(RM) -r _tmp _build
 
 .PHONY: clean