To use boost_build, it is necessary to set BOOST_ROOT in
your environment:

 sh/bash/ksh:
	BOOST_ROOT=%%DATADIR%% ; export BOOST_ROOT
 csh:
	setenv BOOST_ROOT %%DATADIR%%

Note: The default toolchain is gcc.
To override this on a system-wide basis, edit this file:
	%%DATADIR%%/site-config.jam

For an example of a per-user settings file which may be
copied to your home directory, see:
	 %%DATADIR%%/user-config.jam