./mach bootstrap without autoconf installed.

console.log

🌖  🕚  bwinton@10:51/mozilla-central/ (default✗) $ ./mach bootstrap

Please choose the version of Firefox you want to build:
1. Firefox for Desktop
2. Firefox for Android
Your choice:
1

Looks like you have Homebrew installed. We will install all required packages via Homebrew.


We are now installing all required packages via Homebrew. You will see a lot of
output as packages are built.

######################################################################## 100.0%
==> Downloading http://ftpmirror.gnu.org/autoconf/autoconf-2.13.tar.gz
Already downloaded: /Library/Caches/Homebrew/autoconf213-2.13.tar.gz
==> ./configure --program-suffix=213 --prefix=/usr/local/Cellar/autoconf213/2.13 --infodir=/usr/local
==> make install
Error: The `brew link` step did not complete successfully
The formula built, but is not symlinked into /usr/local
Could not symlink share/info/autoconf.info
Target /usr/local/share/info/autoconf.info
is a symlink belonging to autoconf. You can unlink it:
  brew unlink autoconf

To force the link and overwrite all conflicting files:
  brew link --overwrite autoconf213

To list all files that would be deleted:
  brew link --overwrite --dry-run autoconf213

Possible conflicting files are:
/usr/local/share/info/autoconf.info -> /usr/local/Cellar/autoconf/2.69/share/info/autoconf.info
==> Summary
🍺  /usr/local/Cellar/autoconf213/2.13: 28 files, 1021.9K, built in 0 seconds
Error running mach:

    ['bootstrap']

The error occurred in code that was called by the mach command. This is either
a bug in the called code itself or in the way that mach is calling it.

You should consider filing a bug for this issue.

If filing a bug, please include the full output of mach, including this error
message.

The details of the failure are as follows:

CalledProcessError: Command '[u'/usr/local/bin/brew', u'install', u'https://raw.github.com/Homebrew/homebrew-versions/master/autoconf213.rb']' returned non-zero exit status 1

  File "/Users/bwinton/Programming/firefox/mozilla-central/python/mozboot/mozboot/mach_commands.py", line 23, in bootstrap
    bootstrapper.bootstrap()
  File "/Users/bwinton/Programming/firefox/mozilla-central/python/mozboot/mozboot/bootstrap.py", line 134, in bootstrap
    self.instance.install_system_packages()
  File "/Users/bwinton/Programming/firefox/mozilla-central/python/mozboot/mozboot/osx.py", line 188, in install_system_packages
    getattr(self, 'ensure_%s_system_packages' % self.package_manager)()
  File "/Users/bwinton/Programming/firefox/mozilla-central/python/mozboot/mozboot/osx.py", line 314, in ensure_homebrew_system_packages
    self._ensure_homebrew_packages(packages)
  File "/Users/bwinton/Programming/firefox/mozilla-central/python/mozboot/mozboot/osx.py", line 293, in _ensure_homebrew_packages
    subprocess.check_call(cmd + ['install', package])
  File "/usr/local/Cellar/python/2.7.11/Frameworks/Python.framework/Versions/2.7/lib/python2.7/subprocess.py", line 540, in check_call
    raise CalledProcessError(retcode, cmd)