graphics mesa-dri configure error classic dri driver r20 does not exist

[davidheinrichplanner]

configure: error: classic DRI driver 'r20' does not exist
===>  Script "configure" failed unexpectedly.
Please report the problem to x11 at FreeBSD.org [maintainer] and attach the
"/usr/ports/graphics/mesa-dri/work/mesa-18.0.4/config.log" including the
output of the failure of your make command. Also, it might be a good 
idea to
provide an overview of all packages installed on your system (e.g. a
/usr/local/sbin/pkg-static info -g -Ea).
*** Error code 1

Stop.
make[1]: stopped in /usr/ports/graphics/mesa-dri
*** Error code 1

FreeBSD wst00029.geo.umweltwissenschaften.de 11.1-RELEASE-p10 FreeBSD 
11.1-RELEASE-p10 #0: Tue May  8 05:21:56 UTC 2018 
root at amd64-builder.daemonology.net:/usr/obj/usr/src/sys/GENERIC amd64

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