Loongson support; more support for x86 and ARM

Xray-core provides Loongson binaries, but install script doesn't handle this architecture. Adding the following case should be enough:

```sh
loongarch64 )
    MACHINE=loong64
    ;;
```

Also, according to https://stackoverflow.com/a/78630608, there are `i[3456]86` versions of x86, and a plethora of `armv5*`–`armv7*`.