If `git-flow` was installed without explicitly installing `getopt` and `git`
too, it couldn't find those executables. Now it can find those and it can be
used as `git-flow` executable. Note, however, that in order to use `git-flow` as
git subcommand (`git flow`), one needs to install `git` too.
On Darwin, wrap the git-flow binary and set:
FLAGS_GETOPT_CMD=${getopt}/bin/getopt
Without this change, I was getting the following error:
flags:ERROR short flag required for (showcommands) on this platform
