This option was not tested when WARNS was globally lifted in the src tree up
to 6. Drop WARNS back down to unbreak the build; note that this is still
enabling more warnings than it had before the WARNS change, so the gcc build
may need to be independently evaluated at this level.
PR: 252865
Reported-by: Build Option Servey via Michael Dexter
MFC-after: 3 days
Aligns the build with the FreeBSD traditional approach to not build in
contrib/, and to track inter-dependencies between libraries.
With help from: bdrewery
Reviewed by: bdrewery, hselasky
Sponsored by: Mellanox Technologies
MFC after: 2 weeks
Differential revision: https://reviews.freebsd.org/D15648
