CI: ensure make propagates errors and CircleCI fails on doc build failure

This got broken in a recent change to the Makefile

Author: rgommers

Makefile

@@ -12,12 +12,12 @@ clean:
 	-find . -type d -name generated -exec rm -rf {} +
 
 build:
-	-mkdir -p $(BUILDDIR)
-	-cp "$(SOURCEDIR)/_ghpages/_gitignore.txt" "$(BUILDDIR)/.gitignore"
-	-cp "$(SOURCEDIR)/_ghpages/versions.json" "$(BUILDDIR)/versions.json"
-	-cp "$(SOURCEDIR)/_ghpages/index.html" "$(BUILDDIR)/index.html"
-	-touch "$(BUILDDIR)/.nojekyll"
-	-sphinx-build "$(SOURCEDIR)/2021.12" "$(BUILDDIR)/2021.12" $(SPHINXOPTS)
-	-sphinx-build "$(SOURCEDIR)/2022.12" "$(BUILDDIR)/2022.12" $(SPHINXOPTS)
-	-cp -r "$(BUILDDIR)/2022.12" "$(BUILDDIR)/latest"
-	-sphinx-build "$(SOURCEDIR)/draft" "$(BUILDDIR)/draft" $(SPHINXOPTS)
+	mkdir -p $(BUILDDIR)
+	cp "$(SOURCEDIR)/_ghpages/_gitignore.txt" "$(BUILDDIR)/.gitignore"
+	cp "$(SOURCEDIR)/_ghpages/versions.json" "$(BUILDDIR)/versions.json"
+	cp "$(SOURCEDIR)/_ghpages/index.html" "$(BUILDDIR)/index.html"
+	touch "$(BUILDDIR)/.nojekyll"
+	sphinx-build "$(SOURCEDIR)/2021.12" "$(BUILDDIR)/2021.12" $(SPHINXOPTS)
+	sphinx-build "$(SOURCEDIR)/2022.12" "$(BUILDDIR)/2022.12" $(SPHINXOPTS)
+	cp -r "$(BUILDDIR)/2022.12" "$(BUILDDIR)/latest"
+	sphinx-build "$(SOURCEDIR)/draft" "$(BUILDDIR)/draft" $(SPHINXOPTS)