Homebrew/homebrew — pull request #34371 by DrewRWx (2014-11-21 12:23:40+00:00)
Title: Added an option to make boost a soft dependency for assimp.

Currently this removes *boost* from the dependency list and implicitly uses *assimp*'s build system to build with or without *boost* depending on if it is already installed. I like this soft dependency, but I can have the formula explicitly pass the necessary *cmake* flag to build without boost.