Add automatic git versioning. fixes #37

Signed-off-by: Daira Hopwood <daira@jacaranda.org>

protocol/Makefile

@@ -3,6 +3,7 @@ protocol.pdf: protocol.tex zcash.bib incremental_merkle.pdf key_components.pdf
 
 .PHONY: pdf
 pdf:
+	echo "\\\\renewcommand{\\\\docversion}{Version $$(git describe --tags --abbrev=6)}" |tee protocol.ver
 	# If pdflatex fails, touch an input so that 'make' won't think it is up-to-date next time.
 	rm -f protocol.aux
 	pdflatex protocol.tex || touch incremental_merkle.pdf

protocol/protocol.tex

@@ -27,8 +27,10 @@
 
 \setlist[itemize]{itemsep=0.5ex,topsep=0.2ex,after=\vspace{1.5ex}}
 
+\newcommand{\docversion}{Version unavailable (check protocol.ver)}
+\InputIfFileExists{protocol.ver}{}{}
+
 \newcommand{\doctitle}{Zcash Protocol Specification}
-\newcommand{\docversion}{Version 2.0-alpha-2}
 \newcommand{\leadauthor}{Daira Hopwood}
 \newcommand{\coauthors}{Sean Bowe | Taylor Hornby | Nathan Wilcox}