Homebrew is an excellent package manager for OS X. When I went to build Firefox earlier today it had most of the required packages available for me, but was missing autoconf213.
A little digging revealed that there used to be an autoconf213 formula, but it was folded into the spidermonkey formula. In the ticket for Issue 3523 it was decided that this decision should be reversed, but the formula hasn’t reappeared yet.
I dug up the old formula from a prior version of the repo (version control seems magical, sometimes) and dropped it in my
/Library/Formula folder, after which I ran
brew install autoconf. The formula is ‘keg-only’, meaning it doesn’t get linked for general use. Running
brew link autoconf created the appropriate symlinks and the Firefox build ran smoothly.
NOTE: instead of storing it locally, you can install using
brew install http://bit.ly/autoconf213. Afterwards you will still need to link it.
Until the formula comes back, feel free to use the attached copy of the old one. After it reappears, I would use the more current version in the main repository.