Nut USB drivers report a "permission error" without visible reasons
for the error even though permissions are OK (or the driver is run
Nut uses libusb-0.1 API, assuming return cods of < 0. FreeBSD provides
a libusb-0.1 wrapper howerver it uses libusb-1.0 error codes (which
are negative). This set of patches "teaches" nut libusb-1.0 error codes
as produced by FreeBSD.
Network UPS Tools (networkupstools.org) has a project to use libusb-1.0.
This commit is a stopgap fix until our upline implments lubusb-1.0
support in nut.
Submitted by: lev