Cleanups.

* new/virtual-target.jam
  (virtual-target.path): New abstract method. Added so that derived classes
  always define both 'actualize-location' and 'path'.

* new/builtin.jam
  (searched-lib-target.path): Use empty body.


[SVN r18196]

tools/build

@@ -1 +1 @@
-Subproject commit fc2f841c1038e12bd09f55f96b2d52147ece4f3a
+Subproject commit 929daa99797dbaca5e45d7b2a80b8876d838920c