If you are using the common used ext:realurl without a custom extConf
the auto generated config file shouldn’t be added to scm.

These temporary files should never be commited.

This file is part of the configuration for TYPO3.

Typo3 now has an official way of overriding Configuration (AdditionalConfiguration.php).
/t3lib has moved into the /typo3 Directory.
Removed v4 specific ignores because it is deprecated and should no longer be used.
There were ignores missing for the symlinked setup.

To make it easier to handle typo3 under git.
There is a related entry at stackoverflow:
http://stackoverflow.com/questions/11905360/how-best-to-manage-typo3-installations-using-git