XPCShell - Where do I get it?

[Ljósálfr]

I went to run xpcshell so I could test some of the samples on the
http://jslib.mozdev.org/libraries/io/file.js.html page, and I couldn't 
find it under /usr/local/mozilla. The following didn't turn up anything 
either:
> cd /usr/local/mozilla/chrome

> for f in `ls *.jar`;do jar -tf $f | grep -i moz; done

I see it in my copy of the source tree from the CVS.  I can probably 
make that work for me if I have to.  It seems there should be some way 
to install it with xpi, though I know not what that might be.  Any 
suggestions?