Conditionally compiled sources?

From: abingham2 (abingham_at_[hidden])
Date: 2003-10-07 14:42:51

It feels like this should be easy, but I can't quite make it work. I
have some set of source associated with feature-X that I would like
compiled when the user defines USE_FEATURE_X. From what I can tell,
this will define that variable:
bjam define=USE_FEATURE_X

However, I can't figure out how to use that to "enable" the optional
sources. It seems that using two aliases should do the trick, but I
can't figure out the syntax. For instance:

alias feature-x-sources ;
alias feature-x-sources : a.cc b.cc : if-defined(USE_FEATURE_X) ;
exe extreme-pong : main.cc feature-x-sources ;

It's the "if-defined" part I can't figure out. Any ideas? Again, it
seems like this should be easy, but I'm just getting my feet wet with
bjam. Much thanks.

Austin