[Boost-build] Different commands on different platforms?

Subject: [Boost-build] Different commands on different platforms?
From: John Maddock (john_at_[hidden])
Date: 2008-12-02 12:18:23

OK, I give up, I have the seeming trivial:

make gs.check : : @check-gs ;
if $(NT)
{
ECHO "Platform is NT" ;
actions check-gs
{
gswin32c -version
}
}
else
{
ECHO "Platform is not NT" ;
actions check-gs
{
gs -version
}
}

But it always prints "Platform is not NT".  What am I doing wrong?

Also tried switching on $(OS) and $(UNIX) but all the builtin variables seem 
to be undefined in the Jamfile :-(

Cheers, John.