how to fix "Error: Couldn't install: lxml 3.4.4" with Plone 5.0 unified installer on Mac OS X 10.11.1 El Capitan
OS X El Capitan

how to fix "Error: Couldn't install: lxml 3.4.4" with Plone 5.0 unified installer on Mac OS X 10.11.1 El Capitan

According to http://stackoverflow.com/questions/19548011/cannot-install-lxml-on-mac-os-x-10-9 the fix is to update your Xcode command line tools:

xcode-select --install

and then re-run buildout. It worked for me. :)