MFC r330819, r330885, r330934

r330819:
Reject CAMIOGET and CAMIOQUEUE ioctl's on pass(4) in 32-bit compat mode.

These take a union ccb argument which is full of kernel pointers.
Substantial translation efforts would be required to make this work.
By rejecting the request we avoid processing or returning entierly
wrong data.

Reviewed by: imp, ken, markj, cem
Obtained from: CheriBSD
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D14654

r330885:
We need opt_compat.h after r330819 and 330820.

Add opt_compat.h to fix the stand-alone build case.

Sponsored by: Netflix.

r330934:
This should have been += so clean builds work.

Noticed by: hps@