如下:
brew install php56-xhprof
==> Installing php56-xhprof from homebrew/homebrew-php
==> Downloading https://github.com/facebook/xhprof/archive/254eb24dcfa763c76c57b472093ebc4b81af2b7d.tar.gz
######################################################################## 100.0%
==> Patching
Error: Unable to guess PHP branch for Formulary::Formulae::Php56Xhprof
应该是PHP版本有问题,homebrew-php的源码,你尝试安装一下5.3+的版本。