I need to use the right `Ctrl` key in a certain application, but my keyboard doesn't have one. 

The left `Ctrl` key has an entirely different function in this case. How can I emulate the right `Ctrl` key, for example by pressing the right `Alt` button?

I tried the “Right Option acts as Control” feature of [DoubleCommand](http://doublecommand.sourceforge.net/), but sadly, that causes the right `Alt` key to emulate the *left* `Ctrl` key instead of the right `Ctrl`. Aaargh!

Any ideas?