Change the linuxerr.ErrorFromErrno to return an error type and not
a *errors.Error type. The latter results in problems comparing to nil
as <nil><nil> != <nil><*errors.Error>.
In a follow up, there will be a change to remove *errors.Error.Errno(),
which will also encourage users to not use Errnos to reference linuxerr.
PiperOrigin-RevId: 406444419
Removes package syserror and moves still relevant code to either linuxerr
or to syserr (to be later removed).
Internal errors are converted from random types to *errors.Error types used
in linuxerr. Internal errors are in linuxerr/internal.go.
PiperOrigin-RevId: 390724202
Add Equals method to compare syserror and unix.Errno errors to linuxerr errors.
This will facilitate removal of syserror definitions in a followup, and
finding needed conversions from unix.Errno to linuxerr.
PiperOrigin-RevId: 380909667
Adin ScannellandgVisor bot
Zach KoopmansandgVisor bot