add Makefile

"make all/clean/clobber/serve" can be used for building or viewing
documentation locally. The default is to download the mdbook binary
for Linux x86. This can be tuned with Makefile variables or a custom
binary can be used, see Makefile for detail.

Fixes: #78

Author: pohly

.gitignore

@@ -4,3 +4,6 @@ docs/example
 
 # vim
 *.swp
+
+/mdbook
+/mdbook*.tar.gz

Makefile

@@ -0,0 +1,50 @@
+ROOT := $(shell pwd)
+
+# The default is to download the official release binary
+# for x86_64-unknown-linux-gnu. If that default is unsuitable,
+# build your own binary and copy or symlink it here, or
+# override the variable with "make MDBOOK_BINARY=...".
+MDBOOK_BINARY = $(ROOT)/mdbook
+
+# The architecture can be changed. Only Linux .tar.gz files
+# are currently supported, though. See https://github.com/rust-lang-nursery/mdBook/releases
+# for available architectures.
+MDBOOK_ARCH = x86_64-unknown-linux-gnu
+
+# The mdbook version.
+MDBOOK_RELEASE = v0.2.1
+
+# Download URL for mdbook and resulting file.
+MDBOOK_FILE = mdbook-$(MDBOOK_RELEASE)-$(MDBOOK_ARCH).tar.gz
+MDBOOK_URL = https://github.com/rust-lang-nursery/mdBook/releases/download/$(MDBOOK_RELEASE)/$(MDBOOK_FILE)
+
+# As an extra sanity check, the hash of the downloaded file must match before it is used.
+MDBOOK_SHA1 = 5da8d46d09df02d6a671dfbbde20ea85811edbaf
+
+all: $(MDBOOK_BINARY)
+	cd book && $(MDBOOK_BINARY) build
+
+clean:
+	rm -rf docs mdbook-*.tar.gz
+
+clobber: clean
+	rm -f mdbook
+
+# Start mdbook as web server.
+MDBOOK_HOSTNAME = localhost
+MDBOOK_PORT = 3000
+serve:
+	cd book && $(MDBOOK_BINARY) serve --hostname $(MDBOOK_HOSTNAME) --port $(MDBOOK_PORT)
+
+$(MDBOOK_BINARY): $(MDBOOK_FILE)
+	if [ "`sha1sum < $(MDBOOK_FILE) | sed -e 's/ *-$$//'`" != $(MDBOOK_SHA1) ]; then \
+		echo "ERROR: hash mismatch, check downloaded file $(MDBOOK_FILE) and/or update MDBOOK_SHA1"; \
+		exit 1; \
+	fi
+	tar xf $(MDBOOK_FILE)
+	touch $@
+
+$(MDBOOK_FILE):
+	curl -L -O $(MDBOOK_URL)
+
+.PHONY: all clean clobber serve