rdmd shebang on windows

[Bruno]

Good afternoon,

I finally got shebang work on a d file on my windows computer.
As a starter:

```
$ which rdmd
/c/Program Files/D/dmd2/windows/bin/rdmd
```

So, i put it in my main.d file as:

```
#!/c/Program Files/D/dmd2/windows/bin/rdmd
import std.stdio;
void main()  {
     writeln("Hello World!");
}
```

But a space in the shebang path is not a good idea:
```
$ ./main.d
bash: ./main.d: ./c/Program: bad interpreter: No such file or 
directory
```

According to 
https://lists.gnu.org/archive/html/bug-bash/2008-05/msg00052.html 
this is normal behavior. Be it. I created a sim link in the 
directory where my main.d file is:

```
$ ln -s /c/Program Files/D/dmd2/windows/bin/rdmd rdmd
```

And modified my file accordingly:
```
#!./rdmd
import std.stdio;
void main()  {
     writeln("Hello World!");
}
```
And now:
```
$ ./main.d
Hello World!
```

Note that I did not put the --shebang option on the shebang line. 
IF I do so:
```
$ ./main.d
Error: unrecognized switch '--shebang'
        run `dmd` to print the compiler manual
        run `dmd -man` to open browser on manual
Failed: ["dmd", "--shebang", "-v", "-o-", "./main.d", "-I."]
```

Hmm.. Is this a deprecated option? When i run rdmd --help, it is 
still here:
```
$ rdmd --help
...
--shebang          rdmd is in a shebang line (put as first 
argument)
...
```

What would be the purpose of this --shebang option?