I did not PHPCS supports C. Or am I missing something?
Nope, you are spot on :) - I read this as "let's clean up our repositories" not just php-src (which reading back through was my misinterpretation).
Do you have a tool in mind? I see there are a few like indent[1], uncrustify[2] and astyle[3] but I have not used any of them on a project of significant size so I am unsure of the pros and cons of each.
[1]:
http://en.wikipedia.org/wiki/Indent_(Unix)
[2]:
http://uncrustify.sourceforge.net [3]:
http://astyle.sourceforge.net