weston now compiles ! but I could not run it

Weston did not compile ... after this patch it does.

However, more work need to run it.
Still it is not worst than before so it could probably be merged

Here are what I think should be done:
- the preConfigure phase is ugly and pkg_config should do better
- the chmod +s weston-lauch in postInstall can/should be avoided
- still I could not run it, here is one of my try with sudo:

raffalli@delli7:~$ sudo weston-launch --tty /dev/tty9
Password: 
Date: 2013-06-19 CEST
[04:16:11.724] weston 1.1.1
               http://wayland.freedesktop.org/
               Bug reports to: https://bugs.freedesktop.org/enter_bug.cgi?product=Wayland&component=weston&version=1.1.1
               Build:  
[04:16:11.724] OS: Linux, 3.9.6, #1 SMP Sun Jun 16 21:44:09 UTC 2013, x86_64
[04:16:11.724] warning: XDG_RUNTIME_DIR "/run/user/1000" is not configured
correctly.  Unix access mode must be 0700 but is 700,
and XDG_RUNTIME_DIR must be owned by the user, but is
owned by UID 1000.
Refer to your distribution on how to get it, or
http://www.freedesktop.org/wiki/Specifications/basedir-spec
on how to implement it.
couldn't open /root/.config/weston.ini
[04:16:11.724] Loading module '/nix/store/j52vj6ac60pa43dfc3v8bk80hndglsa9-weston-1.1.1/lib/weston/drm-backend.so'
couldn't open /root/.config/weston.ini
[04:16:11.726] initializing drm backend
couldn't open /root/.config/weston.ini
couldn't open /root/.config/weston.ini
[04:16:13.514] using /dev/dri/card0
failed to open /run/opengl-driver/lib/dri/nouveau_dri.so: /run/opengl-driver/lib/dri/nouveau_dri.so: cannot open shared object file: No such file or directory
gbm: failed to open any driver (search paths /run/opengl-driver/lib/dri)failed to load driver: nouveau
failed to load module: libgallium.so.0: cannot open shared object file: No such file or directory
[04:16:13.515] failed to initialize egl
[04:16:13.523] fatal: failed to create compositor