(merge from head) Change to using the stable "-dumpversion" and "-dumpmachine" options of GCC to autoconfigure the toolset.

[SVN r37574]

tools/build

@@ -1 +1 @@
-Subproject commit ff4c9c467822ca1610b73fd8f8675d03c1aa666d
+Subproject commit 4c7ce6370496d784bac8a0383423b9c9a8db4706