Make toolset.using accessible in project-root. It's a great convenience

for testing.


[SVN r18441]

tools/build

@@ -1 +1 @@
-Subproject commit 83ed59d79bce98bbf5e545891747751d1e96b975
+Subproject commit 88503a540cc4c684ee8e3268515c7c60fff6d224