Fixes T5377. The current scripts/update_compat_info.php script works for PHP CompatInfo version 2, but doesn't work with the newer version 3.
There are a few breaking changes in version 3 that had to be addressed:
- PHP 5.3 is required. Whilst Arcanist is generally compatible with PHP 5.2, I don't think that having this dependency presents any real issues because it is purely a development tool that is rarely updated.
- Composer is used for packaging, which makes including the library slightly more complicated. Basically, I had to install PHP_CompatInfo globally with Composer (composer global require "bartlett/php-compatinfo" and then symlink ~/.composer/vendor into externals/includes.