Description:
------------
If you have a c extension defining certain classes, then defining the same class in user land gives the message :

Fatal error: Cannot redeclare class *classname* in *file* on line *linenum*

This is quite confusing, since most people will know to look through all their user land scripts for the redefinition, and few will actually look at their installed extensions to find conflicts.

I recommend changing the error message to:

Fatal error: Cannot redeclare built-in class *classname* in *file* on line *linenum*

Reproduce code:
---------------
<?php

class Exception {
}

?>

Expected result:
----------------
Fatal error: Cannot redeclare built-in class *classname* in *file* on line *linenum*

Actual result:
--------------
Fatal error: Cannot redeclare class *classname* in *file* on line *linenum*