Add command to run syscalls directly

[trufae]

Use r2 knowledge to resolve syscall numbers . Make it work like dxc but calling syscalls instead of functions.

We will ned to use the code generation apis to construct the snippet to call that and return from it

[trufae]

As an example https://github.com/nowsecure/r2frida/blob/master/plugins/inject-exit.js

[trufae]

On iOS and macOS we can just use dxc with the syscall symbol

[0x00000000]> \dxc syscall 0x2000001
DetachReason: FRIDA_SESSION_DETACH_REASON_PROCESS_TERMINATED
Target process terminated
[0x00000000]>

[trufae]

i have implemented dxs, but the list of syscalls is limited, it may use the ones defined in r2

[trufae]

Do we want to have \asl inside r2frida to enumaerte the target syscalls :?

[trufae]

closing because we have https://github.com/nowsecure/r2frida/issues/395