  
  build/_build/html/d2l-zh.zip: $(OBJ) $(DEPS)
  	cd build; zip -r $(patsubst build/%, %, $@ $(DEPS)) chapter*
  
  build/%: %
  	@mkdir -p $(@D)
  	@cp -r $< $@
  
  html: $(DEPS) $(FRONTPAGE_DEP) $(OBJ)
 
</s> remove html: $(DEPS) $(OBJ)
 </s> add html: $(DEPS) $(FRONTPAGE_DEP) $(OBJ) </s> remove     url='https://github.com/mli/gluon-tutorials-zh',
 </s> add     url='http://www.diveintodeeplearning.org', </s> remove 	rm -rf build/chapter* build/_build $(DEPS) $(PKG)
 </s> add 	rm -rf build/chapter* build/_build build/img build/data build/environment.yml build/README.md $(PKG)
 </s> remove ORIGN_DEPS = $(IMG_NOTEBOOK) $(wildcard data/*) environment.yml README.md
DEPS = $(patsubst %, build/%, $(ORIGN_DEPS))
 </s> add IMG_NOTEBOOK = $(filter-out $(FRONTPAGE_DIR), $(wildcard img/*))
ORIGIN_DEPS = $(IMG_NOTEBOOK) $(wildcard data/*) environment.yml README.md
DEPS = $(patsubst %, build/%, $(ORIGIN_DEPS)) </s> remove FRONTPAGE = $(wildcard img/frontpage/*)
IMG_NOTEBOOK = $(filter-out $(FRONTPAGE), $(wildcard img/*))
 </s> add FRONTPAGE_DIR = img/frontpage
FRONTPAGE = $(wildcard $(FRONTPAGE_DIR)/*)
FRONTPAGE_DEP = $(patsubst %, build/%, $(FRONTPAGE))
# Copy everything to build/.
  
  build/_build/html/d2l-zh.zip: $(OBJ) $(DEPS)
  	cd build; zip -r $(patsubst build/%, %, $@ $(DEPS)) chapter*
  
# Copy everything to build/.
  build/%: %
  	@mkdir -p $(@D)
  	@cp -r $< $@
  
  html: $(DEPS) $(FRONTPAGE_DEP) $(OBJ)
keep keep keep add keep keep keep keep keep
 add frontpage dep, clean unused files in build/, and modify Makefile 
Makefile