Update the Makefile to support dependency checking for JS and LESS

We can now build less files that are separate from the main css.

Makefile

@@ -1,30 +1,49 @@
 export PATH := $(PATH):build/bin
 TEMPLATE_DIR := wdn/templates_4.0
+TEMPLATE_LESS := $(TEMPLATE_DIR)/less
+TEMPLATE_CSS := $(TEMPLATE_DIR)/css
+TEMPLATE_JS := $(TEMPLATE_DIR)/scripts
+TEMPLATE_RJS := $(TEMPLATE_JS)/compressed
 
 GIT := git
 
 LESSC := lessc
 LESSC_FLAGS := --yui-compress --line-numbers=comments
-LESS_OBJS := all.less
-LESS_OUT ?= $(LESS_OBJS:.less=.css)
+
+LESS_MIXINS := $(TEMPLATE_LESS)_mixins/all.less
+LESS_MIXINS_DEPS := $(filter %.less, $(shell $(LESSC) -M $(LESS_MIXINS) .tmp))
+LESS_ALL := all.less
+LESS_ALL_OUT := all.css
+CSS_OBJS := \
+	$(TEMPLATE_CSS)/$(LESS_ALL_OUT) \
+	$(TEMPLATE_CSS)/layouts/unlalert.css
 
 RJS := r.js
 RJS_FLAGS :=
-JS_BUILD_CONF := build/build.js
+RJS_BUILD_CONF := build/build.js
+JS_ALL_OUT := $(TEMPLATE_RJS)/all.js
+JS_DEPS := $(TEMPLATE_JS)/*.js
 
 SMUDGE_STATUS := $(shell $(GIT) config filter.rcs-keywords.smudge)
 
 all: less js
 
-less:
-	$(LESSC) $(LESSC_FLAGS) $(TEMPLATE_DIR)/less/$(LESS_OBJS) $(TEMPLATE_DIR)/css/$(LESS_OUT)
+less: $(CSS_OBJS)
+
+$(shell $(LESSC) -M $(TEMPLATE_LESS)/$(LESS_ALL) $(TEMPLATE_CSS)/$(LESS_ALL_OUT))
+
+$(TEMPLATE_CSS)/%.css: $(TEMPLATE_LESS)/%.less $(LESS_MIXINS_DEPS)
+	@mkdir -p $(@D)
+	$(LESSC) $(LESSC_FLAGS) $< $@
+
+js: $(JS_ALL_OUT)
 
-js:
-	$(RJS) -o $(JS_BUILD_CONF) $(RJS_FLAGS)
+$(JS_ALL_OUT): $(RJS_BUILD_CONF) $(JS_DEPS)
+	$(RJS) -o $(RJS_BUILD_CONF) $(RJS_FLAGS)
 
 clean:
-	rm -rf $(TEMPLATE_DIR)/css
-	rm -rf $(TEMPLATE_DIR)/scripts/compressed
+	rm -rf $(TEMPLATE_CSS)
+	rm -rf $(TEMPLATE_RJS)
 
 dist: all
 	@if test -z "$(SMUDGE_STATUS)"; then \