I built Qt for pi 3. I used the linux-rasp-pi3-g++ device. I followed all the recommendations from https://wiki.qt.io/RaspberryPi2EGLFS. But after starting the application, I get a flickering white screen and the following messages in the console:

QOpenGLFramebufferObject: Framebuffer incomplete attachment.
QOpenGLFramebufferObject: Framebuffer incomplete attachment.
QOpenGLFramebufferObject: Framebuffer incomplete attachment.
QOpenGLFramebufferObject: Framebuffer incomplete attachment.
QOpenGLShaderProgram: could not create shader program
QOpenGLShaderProgram: could not create shader program
QOpenGLShaderProgram: could not create shader program
QOpenGLShaderProgram: could not create shader program
shader compilation failed:
""
QOpenGLShaderProgram::uniformLocation(qt_Matrix): shader program is not linked
QOpenGLFramebufferObject: Framebuffer incomplete, missing attachment.
QOpenGLFramebufferObject: Unsupported framebuffer format.
QOpenGLFramebufferObject: Unsupported framebuffer format.
QOpenGLFramebufferObject: Framebuffer incomplete, missing attachment.