Compiling 1.3.0 or 1.3.1 results in this error message when loading php -v. As a result, phalcon is not available in PHP. It works flawless with 1.2.6.
PHP Warning: PHP Startup: Unable to load dynamic library '/usr/lib/php5/20121212/phalcon.so' - /usr/lib/php5/20121212/phalcon.so: undefined symbol: php_pdo_get_dbh_ce in Unknown on line 0
System: Ubuntu 12.04 LTS 32bit in a Vagrant VM.