mxcl/homebrew — pull request #15780 by manphiz (2012-10-31 09:51:55+00:00)
Title: Only block default macports path instead of whole /opt.

* If all paths that begin with "/opt" are stripped then it will break
Homebrew installed under /opt as well.

I guess the purpose for this is to prevent macports from polluting the building process of Homebrew formulae, but stripping whole /opt* is kind of overkill. I'm not sure I'm looking at the right place, but as I installed Homebrew at /opt/homebrew, some formula depending on other formulae does fail to build due to stripping of $LDFLAGS containing -L/opt/homebrew/*.