a0c9372baa
Assume BUCK has applied my commit to use set -e when running a genrule(). This allows us to use ';' in all genrule commands and trust the build will stop if any of the single statement terminates with a non-zero exit status. $SRCDIR is a cleaner reference to the sources of a genrule(), fixing an ugly reference to the (supposedly hidden) __srcs directory. Add a comment about the version generator, BUCK wants to make genrule output fully cacheable, which requires rules to be idempotent. Change-Id: I938450ed81675330e979d76721e0ba971d30d0e2