Bug#785519: The Bug is gone.
xserver-xorg-video-intel works fine now. I don't know what change in my system is responsible for this. Perhaps the newer kernel 4.1.0-2-amd64. Thanks (Martin Ziegler)
mesa: Changes to 'ubuntu'
debian/changelog |7 +++ debian/control |4 ++-- debian/rules |2 +- 3 files changed, 10 insertions(+), 3 deletions(-) New commits: commit 3542723ae751512163eb705170aca9b33e32c972 Author: Timo Aaltonen Date: Fri Oct 2 17:34:33 2015 +0300 control, rules: Disable LLVM