[Xcb] where to find xproto.pc ?

[Florent Monnier]

> You can easily just download, build, and install the modular xproto
> (proto/X11) into a prefix *other than* /usr, avoiding conflict with your
> packaging system.  You can then build XCB against that modular xproto.

I don't know what is, and where to find this "modular xproto", so I've asked 
to Google:  http://www.google.com/search?q=modular+xproto

Could you point me on the good answer ?