Fix a couple of fallouts from the default build change.
* new/make.jam
(make): Pass 'default-build' in the right position.
* new/targets.jam
(basic-target): Use empty property-set if no default-build is passed.
(main-target): Use 'raw' to test property-set for emptines. The string
emptyness test that use to be there does not works for property-sets.
[SVN r18440]
Vladimir Prus