Homebrew/homebrew — pull request #25820 by dtrebbien (2014-01-11 21:33:09+00:00)
Title: Build and install `zopflipng` when compiling from HEAD

The zopflipng command line utility was added after the 1.0.0 release:
https://code.google.com/p/zopfli/source/browse/README.zopflipng

If compiling zopfli from HEAD, also build and install zopflipng.