Weston drm-backend.so seems to fail with Mesa master and LIBGL_ALWAYS_SOFTWARE=1

Hi

I first noticed this on UDL/Displaylink, but now I see this on QXL too It fails to initialize EGL, 0x3001 , then it stops. I notice it selects a (null) driver, not sure if that is relevant. This issue might have been happening longer. or maybe I compiled my Mesa wrong. I tried to include everything relevant...

relevant variables:

WESTON_PLUGIN_PATH=/opt/lib/i386-linux-gnu/weston
XDG_SESSION_TYPE=tty
XDG_SESSION_CLASS=user
COGL_RENDERER=egl_wayland
XDG_SEAT=seat0
LIBGL_ALWAYS_SOFTWARE=1

Weston log output:

Date: 2019-01-09 UTC
[03:45:43.647] weston 5.0.90
               https://wayland.freedesktop.org
               Bug reports to: https://gitlab.freedesktop.org/wayland/weston/issues/
               Build: 5.0.0-110-g13dda10f+
[03:45:43.649] Command line: weston
[03:45:43.650] OS: Linux, 4.19.0-1-686-pae, #1 SMP Debian 4.19.12-1 (2018-12-22), i686
[03:45:43.652] Using config file '/home/beccaholic/.config/weston.ini'
[03:45:43.653] Output repaint window is 7 ms maximum.
[03:45:43.654] Loading module '/opt/lib/i386-linux-gnu/libweston-5/drm-backend.so'
[03:45:43.660] initializing drm backend
[03:45:43.671] logind: session control granted
[03:45:43.676] using /dev/dri/card0
[03:45:43.678] DRM: supports universal planes
[03:45:43.678] DRM: does not support atomic modesetting
[03:45:43.679] DRM: supports picture aspect ratio
[03:45:43.680] Loading module '/opt/lib/i386-linux-gnu/libweston-5/gl-renderer.so'
pci id for fd 14: 1234:1111, driver (null)
[03:45:43.717] EGL client extensions: EGL_EXT_client_extensions
               EGL_EXT_device_base EGL_EXT_device_enumeration
               EGL_EXT_device_query EGL_EXT_platform_base
               EGL_KHR_client_get_all_proc_addresses EGL_KHR_debug
               EGL_EXT_platform_wayland EGL_EXT_platform_x11
               EGL_MESA_platform_gbm
[03:45:43.718] failed to initialize display
[03:45:43.718] EGL error state: EGL_NOT_INITIALIZED (0x3001)
[03:45:43.719] failed to initialize egl
[03:45:43.720] fatal: failed to create compositor backend
[03:45:43.720] Internal warning: debug scope 'drm-backend' has not been destroyed.

if it is relevant, this is what I compiled Mesa with

meson --buildtype=plain --prefix=$INSTALLDIR --libdir=$INSTALLDIR/lib/$(dpkg-architecture -qDEB_HOST_MULTIARCH) -Dgles1=true -Dgles2=true -Dplatforms=x11,wayland,drm -Dgallium-drivers=nouveau,svga,r300,r600,swrast,radeonsi,virgl -Ddri-drivers=r200,nouveau,i915,i965 -Dosmesa=gallium -Dgallium-xa=true -Dgbm=true -Dshared-glapi=true -Dshared-llvm=true -Dvulkan-drivers=intel,amd -Dllvm=true build 

Thanks