Refactoring.

* new/targets.jam
    (main-target.apply-default-build): New rule, extracted from 'generate'.
    (main-target.generate): Use the above.


[SVN r17754]

tools/build

@@ -1 +1 @@
-Subproject commit 3b46c3ac8a010d4deac447a2aae943b78cda99ab
+Subproject commit 613e8c816785bda979f3443f38ea9b872d7b566a