[Boost-build] build boost_1_42_0 on Mac OSX specifying base sdk 10.4 from 10.5

Subject: [Boost-build] build boost_1_42_0 on Mac OSX specifying base sdk 10.4 from 10.5
From: Jeff Flinn (TriumphSprint2000_at_[hidden])
Date: 2010-07-07 16:43:54

Can anyone see what the problem with this command line is:

bjam --toolset=darwin --toolset-root=/usr/bin/gcc-4.0 --layout=versioned 
architecture=combined sdkroot=10.4 link=static debug release stage

I'm trying to specify the base sdk as 10.4 and build with xcode's gcc 
4.0.1 from a Leopard Mac. The above minus toolset-root and sdkroot 
options properly builds boost for 10.5.

Thanks, Jeff