PHP bindings for libvirt virtualization toolkit Formula was removed
Last version was
php55-libvirt requires the following formulae to be installed:
autoconf 2.69 Automatic configure script builder
pkg-config 0.29.2 Manage compile and link flags for libraries
libvirt 4.2.0 C virtualization API

Recent formula history

Mike McQuaid Deprecate tap.
Baptiste Fontaine php55-libvirt: audit fixes
Andy Blyler fix style issues
Jack Nagel Move abstract classes out of Formula directory
Jack Nagel Revert "Move abstract classes out of Formula directory"

Formula code at GitHub