[Boost-build] How to use command line option -s?

Subject: [Boost-build] How to use command line option -s?
From: Boris Schaeling (boris_at_[hidden])
Date: 2009-08-06 20:59:44

I'm trying to set a variable with the command line option -s:

bjam -sx=y

The Jamfile contains:

ECHO $(x) ;

I would expect to see y but I get an empty line. Isn't -s meant to set any  
variables? How do I set a variable on the command line?

Boris