Similar to libexec/, do the same with lib/. Make WARNS=6 the norm and
lower it when needed.
I'm setting WARNS?=0 for secure/. It seems secure/ includes the
Makefile.inc provided by lib/. I'm not going to touch that directory.
Most of the code there is contributed anyway.
The devinfo library provides access to the kernel's internal device
hierarchy and to the I/O resource manager. The library uses a
sysctl(9) interface to obtain a snapshot of the kernel's state which
is then made available to the application.