mxcl/homebrew — pull request #14478 by greshny (2012-08-27 11:41:39+00:00)
Title: fixed MacOS::XQuartz.prefix

I was not able to install ghostscript on OS X 10.8.1, I got exception:

``brew install ghostscript
==> Downloading http://downloads.ghostscript.com/public/ghostscript-9.06.tar.gz
Already downloaded: /Library/Caches/Homebrew/ghostscript-9.06.tar.gz
Error: undefined method `/' for nil:NilClass
Please report this bug:
https://github.com/mxcl/homebrew/wiki/bug-fixing-checklist
/usr/local/Library/Homebrew/macos/xquartz.rb:64:in `lib'
/usr/local/Library/Formula/ghostscript.rb:42:in `install'
/usr/local/Library/Homebrew/build.rb:102:in `install'
/usr/local/Library/Homebrew/formula.rb:219:in `brew'
/usr/local/Library/Homebrew/formula.rb:521:in `stage'
/usr/local/Library/Homebrew/extend/fileutils.rb:22:in `mktemp'
/usr/local/Library/Homebrew/formula.rb:517:in `stage'
/usr/local/Library/Homebrew/formula.rb:214:in `brew'
/usr/local/Library/Homebrew/build.rb:82:in `install'
/usr/local/Library/Homebrew/build.rb:44
/usr/local/Library/Formula/ghostscript.rb:39``

This small changes will solve problem.

Thanks.