It seems that after upgrading the CI servers to phpcs 1.5.2, some "Default timezone is required since PHP 5.4" warnings have started to be shown for every file checked.
That Sniff is part of the "phpcompatibility" standard, that we have incorporated to our "moodle" one.
This is about to research why this has started happening now and fix it (it shouldn't).
The easiest solution is to set "date.timezone" in php.ini, but before that we need to understand why it was not happening before phpcs 1.5.2.
That is, ciao