Providing default WARNS

[Kyle Evans]

Hi,

I have a proposal/review open for setting a default WARNS=6 for all
builds within the src tree. This will provide coverage to deeper parts
of the build that currently have 0 warnings added. It will also
eliminate the need to worry about it unless we have warnings in new
stuff that should be fixed, and improve the overall quality of the
tree.

I've added a couple people that I suspect may be interested, but
please feel free to chime in: https://reviews.freebsd.org/D26397

Thanks,

Kyle Evans