APC User Cache Formula was removed
Last versions were
php54-apcu requires the following formulae to be installed:
autoconf 2.69 Automatic configure script builder
pcre 8.42 Perl compatible regular expressions library

Recent formula history

Mike McQuaid Deprecate tap.
Mike McQuaid php54-apcu: use <<~EOS.
Jan Viljanen Add missing conflict between ph54 apc and apcu (#3461)
Andy Blyler apcu 4.0.11
Andy Blyler php5*-apcu 4.0.8

Formula code at GitHub