Problem with rdmd

[eles]

On Linux 64

$chmod +x htest
$cat ./htest
#!/usr/bin/env rdmd
import std.stdio;
void main() {
        writeln("hello world!");
}

then:

$./htest
Error: cannot read file ./htest.d
Failed: 'dmd' '-v' '-o-' './htest.d' '-I.'

OTOH:

$cp htest htest.d
$./htest.d
hello world!

It seems that rdmd expects the script to bear the .d extension. 
This is not a very good choice, at least when writing git helper 
scripts.

For example, a "$git command" command would eventually try to 
execute the executable (script):

$git-command

The problem is that that line expects git-command, not 
git-command.d.

A workaround for this?

Thanks