mxcl/homebrew — pull request #16547 by manphiz (2012-12-13 09:57:47+00:00)
Title: Add TeX support to gnuplot and use opt_prefix

* Add TeXDependency class to detect TeX installation and add option to
enable TeX support.
* Use opt_prefix for keg_only dependencies to avoid breakage when keg
updates.

Note ```env :userpaths``` is needed for latex command in user set path.

Also I think TeXDependency may be beneficial to be included in ```Library/Homebrew/Requirement.rb```.