Log Message:
Fix typo or error.  It was checking for wrong header name (that
never existed as far as I can tell). It should have first letter
capitalized.

This error was in the original version of the builtin.mk
and when the builtin.mk structure was changed the error
was brought with it.

This update means that packages (like metacity) that depend
on Xcomposite now may no longer depend on it since they
can use the native (Xorg) version.

This would only occur for systems using xorg as the X11_TYPE.
(I need to confirm this -- should I do bump revisions of these
packages?)