[SOLVED] Error while installing Mesa, Error: xcb/xcb.h missing

Hello, I'm having trouble installing Mesa from the BLFS book. Everything seems to work out ok until I type "ninja" to start the compilation. I get an error saying xcb/xcb.h is missing.
I can confirm xcb.h exists in /usr/X11/include/xcb/xcb.h

How can I point the mesa installation to this file?
Sorry if this is obvious, I'm still learning.

Thanks,
Johhn