linux: add new syscall numbers

[emaste]

Also 32-bit arm? Also we ought to take a look at some deduplication at some point.

[trasz]

In D30193#678074, @emaste wrote:

Also 32-bit arm? Also we ought to take a look at some deduplication at some point.

Is 32-bit ARM linuxulator actually a thing? That syscalls.master looks quite different to the others, and I'm not sure I want to spend time on it.

As for deduplication - this might be somewhat hard to do, given that in Linux, each architecture has a slightly different syscall numbers.

[emaste]

New architectures use common syscall numbers, I think arm64 and riscv64 will be able to share

[trasz]

(Tinderboxed.)