Kick dd out of the build tools club

[imp]

Summary

Make sure we can use dd status=none before using it. That way, it doesn't have to be a build tool.

Test Plan

compile from older freebsd 10's and see if it works.
10.3R has dd status=none, and it works there when I change it to 'fred=none' in the test (so it doesn't add fred=none, and it doesn't print an obnoxious error message).

[imp]

sys/boot/Makefile.inc

21 ↗

(On Diff #22411)

Clearly I'd need to change this to status=none for the commit. :)

[emaste]

Looks like a good idea, without fred and perhaps with an update in the comment.

sys/boot/Makefile.inc

19 ↗

(On Diff #22411)

Minor nit, this sounds like status=none was added to the dd command for reproducible builds, not to the individual invocations.