New Device / eglfs on Raspberry Pi 4 with Raspbian Buster

For new Raspberry PI 4 with Raspbian Buster installed, we need a solution to get hardware accelaration eglfs running again. No X, no wayland.

• New SOC Broadcom 2711
• New Cores ARM Cortex-A72
• Rasbian changed default to mesa vc4-fkms-v3d
• Broadcom videocore driver is still there /opt/vc but not working with RPi4?

Perhaps we can get a new qmake.conf here: /qtbase/mkspecs/devices/ for the Raspberry Pi 4 Device to get the eglfs running.

First try:

I build 5.12.4 with the existing device linux-rasp-pi3-vc4-g++. My qml code is running with the following message and a very poor performance:
>> Running on a software rasterizer (LLVMpipe), expect limited performance.

Second try:

I disabled the vc4-fkms-v3d driver and uninstalled the mesa stuff. Linked to /opt/vc/lib/libbrcmGLESv2.so and /opt/vc/lib/libbrcmEGL.so

Build 5.12.4 with linux-rasp-pi3-g++ Device succsessful.-> config.summary shows: 

EGLFS Raspberry Pi ................... yes

My qml code is starting, console log OK but no qml widget on the screen. Aborted without debug informations.