add #12: prepare English supports

pdf/zh-cn/Makefile

@@ -0,0 +1,28 @@
+title = '高速上手 C++11/14/17'
+filename = 'modern-cpp-tutorial'
+outputname='modern-cpp-tutorial'
+
+all: pdf
+
+pdf: markdown
+	@echo "Compiling PDF file..."
+	@pandoc -s $(filename).md -o $(filename).pdf \
+		--title-prefix $(title) \
+		--listings -H meta/cpp-listings.tex \
+		--template=meta/template.tex \
+		--normalize \
+		--smart \
+		--latex-engine=`which xelatex`
+	@echo "Done."
+	@rm *.md
+
+markdown:
+	@echo "Copy markdown files..."
+	@cp -r ../../book/zh-cn/* .
+	@echo "Aggregating markdown files..."
+	@python3 aggregator.py
+
+clean:
+	rm -rf *.md *.pdf
+
+.PHONY: markdown pdf clean