Example doesn't return error code

Running the example code with a none existence file descriptor returns 18446744073709551607

You can check with using the following code

```
import syscalld : syscall, WRITE;

size_t write(size_t fd, string buf)
{
return syscall(WRITE, fd, cast(size_t) buf.ptr, cast(size_t) buf.length);
}

void main()
{
import std.stdio;
size_t stdout = 1;
writeln(write(1900000000000, "Hello\n"));
}
```

Start by running the example with the nonexistent file descriptor shown in the issue and inspect the syscall interface used by write. Determine why the result is 18446744073709551607 and define the expected error-code behavior before adding a regression check.

Written by the indexing model from the issue text.