Optimization:

* build/toolset.jam
  Setting variables on targets includes two parts: deciding
  what flags are applicable and applying the flags. The first part requires
  checking property sets and is pretty slow. It's optimised by cacheing.


[SVN r26543]

tools/build

@@ -1 +1 @@
-Subproject commit 28d8b4c46b303a78b1336ce702bf66a0ce570528
+Subproject commit e24570215faec53f25096f7bc82ad168239caa49