r278328: fails to build kernel due to /usr/src/sys/kern/subr_bus.c: undefined reference to `memchr'

Recent sources seem to fail in buildkernel with

[...]
--- kernel ---
linking kernel
subr_bus.o: In function `devctl2_ioctl':
/usr/src/sys/kern/subr_bus.c:(.text+0x6284): undefined reference to `memchr'
*** [kernel] Error code 1


Regards,

oh