freebsd stable - Jul 2019 - Rel. 11.3: Kernel doesn't compile anymore :(

Trying to compile my custom kernel in Rel. 11.3 results in this:

[code]--- kernel.full ---
linking kernel.full
atomic.o: In function `atomic_add_64':
/usr/obj/usr/src/sys/E1R11V1/./machine/atomic.h:629: multiple definition of
`atomic_add_64'
opensolaris_atomic.o:/usr/src/sys/cddl/contrib/opensolaris/common/atomic/i386/opensolaris_atomic.S:71:
first defined here
*** [kernel.full] Error code 1[/code]

Same config worked with 11.2

The offending feature is either
   options ZFS
or
   device dtrace
(Adding any of these to the GENERIC config gives the same error.)

This happens only when building for i386. Building amd64 with these
options works.