I started working on Xserver build, and hence I can anwser my own
questions:

> Is it possible to cross-build X using the build machinery tools? It
> seems possible, but I'd like a confirmation.

The answer seems to be no, since some tools such as imake are built for
the target platform, but I'm not sure. I'm building natively, it removes
one difficulty.
 
> Is it possible to build without local.tar.gz and contrib.tar.gz?
> Is it possible to only build the X server? That's what is iinteresting
> for now: we don't really care about xclock and friends for now...

I'm doing a make build in xsrc. I get Makefile generation, make includes
and make depend, then I interupt the build, I go to
xsrc/xc/programs/Xserver and I do a make. 

I need to make in xsrc/xc/lib/Xau, xsrc/xc/lib/Xdmcp, xsrc/xc/lib/font,
xsrc/xc/lib/lbxutil because the X server depends on this.

I'm able to build the X server, but when I run it, it fails because it
attemps to set keyboard raw mode (using a wscons ioctl) on ttyE0
(obviously instead of wskbd0). I haven't figured out what's wrong yet.

-- 
Emmanuel Dreyfus
UNIX *is* user friendly. It is just a bit selective about his friends
manu@netbsd.org