Update makefile to properly update submodules

Makefile

@@ -1,17 +1,28 @@
 .PHONY: all
 all: install
 
-25th-hour.heic:
-	git submodule update external/wallpapper
-	swift run --package-path external/wallpapper \
+PRE := "[25th-hour]"
+
+external/wallpapper/.git:
+	@echo ${PRE} Fetching submodule wallpapper
+	@git submodule update --init external/wallpapper
+
+external/macos-wallpaper/.git:
+	@echo ${PRE} Fetching submodule mcaos-wallpaper
+	@git submodule update --init external/macos-wallpaper
+
+25th-hour.heic: external/wallpapper/.git
+	@echo ${PRE} Building dynamic wallpaper
+	@swift run --package-path external/wallpapper \
 			wallpapper -i wallpapper.json -o 25th-hour.heic
 
 .PHONY: install
-install: 25th-hour.heic
-	git submodule update external/macos-wallpaper
-	swift run --package-path external/macos-wallpaper \
+install: 25th-hour.heic external/macos-wallpaper/.git
+	@echo ${PRE} Setting wallpaper on all visible desktops
+	@swift run --package-path external/macos-wallpaper \
 			wallpaper set 25th-hour.heic
 
 .PHONY: all
 clean:
-	rm -f 25th-hour.heic
+	@echo ${PRE} Removing dynamic wallpaper
+	@rm -f 25th-hour.heic