Homebrew/homebrew — pull request #33828 by zwaldowski (2014-11-02 18:14:12+00:00)
Title: gtk+3: Conditionalize at-spi2-atk dependency for X11

Though `gtk+3` now has a `--without-x11` flag, it cannot actually be use unless XQuartz is installed because `at-spi2-core` (via `at-spi2-atk`) has a hard dependency on X11.