We currently print unsupported consts to console during make extract.
But this is not very useful as there are too many output now.
This also does not allow to understand what's unsupported
in newly checked-in descriptions, or what's unsupported in all current
decriptions.
Save unsupported consts to the const files instead.
This solves all of the above problems.
open is not present on arm64, only openat.
accept is not present on 386, only accept4.
Duplicate all open/accept specializations with
corresponding openat/accept4 specializations
to enable testing on 386/arm64.
