Merge pull request scrapy#1319 from yarikoptic/fix-fail-if-docsbuild-fails

[MRG+1] BF: fail if docs failed to build

Author: dangra

docs/Makefile

@@ -24,9 +24,14 @@ help:
 	@echo "  changes   to make an overview over all changed/added/deprecated items"
 	@echo "  linkcheck to check all external links for integrity"
 
-
-build: 
+build-dirs:
 	mkdir -p build/$(BUILDER) build/doctrees
+
+build: build-dirs
+	sphinx-build $(ALLSPHINXOPTS)
+	@echo
+
+build-ignore-errors: build-dirs
 	-sphinx-build $(ALLSPHINXOPTS)
 	@echo
 
@@ -59,7 +64,8 @@ linkcheck: build
 	@echo "Link check complete; look for any errors in the above output " \
 	      "or in build/$(BUILDER)/output.txt"
 
-linkfix: linkcheck
+linkfix: BUILDER = linkcheck
+linkfix: build-ignore-errors
 	$(PYTHON) utils/linkfix.py
 	@echo "Fixing redirecting links in docs has finished; check all " \
 	      "replacements before committing them"