drm.ko/radeon build stops with specialreg.h

[Super Bisquit]

FreeBSD SNAPSHOT-9 from people.freebsd.org/~nwhitehorn not ppc64. In the
directories of /usr/src/sys/modules/drm/ and of
/usr/src/sys/modules/drm/radeon the build breaks with specialeg.h not found.
Using find -f /|grep specialreg.h only leaves me with
/usr/src/sys/(x86-variant)/include/speialreg.h.
At the same time, make complains of object directory not being changed.