[development] coding standard question

[Nedjo Rogers]

The documented standard is to use upper case for all constants, see the 
Constants section at:

http://drupal.org/coding-standards

Maybe we should add something like "This includes pre-defined PHP constants 
like TRUE, FALSE, and NULL."

A year ago we cleaned up these constants in core, 
http://drupal.org/node/72204, but since then lower case instances have crept 
back in.