BUILDLINK_PREFIX.<pkg> for X11 related packages

["OBATA Akio" <obache%netbsd.org@localhost>]

Hi!

Now failed to build graphics/cal3d-examples with native X on NetBSD-5 
(pkg/40457),
becaouse builtin glut exists and BUILDLINK_PREFIX.glut point to /usr, not 
${X11_BASE}.
I don't know about other packages, but I can't find assginment to 
BUILDLINK_PREFIX
in any builtin.mk file.  So other packages also point to wrong directory.

Where BUILDLINK_PREFIX.<pkg> should be assined? each builtin.mk?

-- 
"Of course I love NetBSD":-)
OBATA Akio / obache%NetBSD.org@localhost