Sync
Note import of dhcpcd-6.6.7
Make the building of INET optional.
As both INET and INET6 are now options, it's possible to build dhcpcd
without both. When built this way it will just report carrier events.
Bump UFS1 extended attribute max name length to 256

For extended attribute name max length, kernel filesystem-independant
code use either EXTATTR_MAXNAMELEN (BSD API) or XATTR_NAME_MAX (Linux API),
which are both defined as KERNEL_NAME_MAX and fits Linux limit of 255
without training \0.

UFS1 code had a lower limit that broke Linux compatibility. We can bump
the limit without sacrifying backward compatibility, because:

1) There is no API exposing this limit outside the kernel. Upper kernel
layers have a larger limit handle the increase without a hitch

2) Each attribute has its own backing store in the fileystem, the name
of the backing store matching the attribute name. A newer kernel can
create/read/write backing store for longer attribute names and will
have no problem with existing shorter names.
Consistently take the interface down when the radio swicth is off.