BOOST_ROOT = $(.boost-build-file:D) ; if --v2 in $(ARGV) { if $(JAM_VERSION:J="") < 030103 { ECHO "error: Boost.Jam 3.1.3 or later required" ; EXIT ; } else { JAMFILE = [Jj]amfile.v2 ; boost-build tools/build/new ; } } else { boost-build tools/build ; }