NetBSD-specific changes for xf86-input-keyboard

[Thomas Klausner]

These patches mirror the commit history of changes done to
xf86-input-keyboard in the NetBSD xsrc repository (except perhaps
for timing between patches for different files).

I'm willing to squash or edit patches to reduce the number of diffs;
please advise on what you want combined in this way.

Other suggestions welcome too, for example for patch 21's autoconf
code for machine architecture detection.