Unbreak notfile targets and gettext message catalog update.

* build/virtual-target.jam
  (abstract-file-target.grist): Handle the case where property list is empty.
  (notfile-target.path): New rule.


[SVN r26102]

tools/build

@@ -1 +1 @@
-Subproject commit 3d42ee5bea08ba41a65aa3dfc1b0e97ff80ba6a7
+Subproject commit 14ce4c5cac331a8693bbc56c86099f11551a9011