A unified Sybase-DB style driver for PDO Formula was removed
Last version was
php53-pdo-dblib requires the following formulae to be installed:
autoconf 2.69 Automatic configure script builder
freetds 1.00.91 Libraries to talk to Microsoft SQL Server and Sybase databases

Recent formula history

Mike McQuaid Deprecate tap.
Andreas Braun Add description for pdo-dblib formula
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