Removed hidden prototype from builtins, i.e., deleting an overridden function on builtins will not make the original function reappear.

Added NetBSD support for scons build.

Performance improvements on all platforms.


git-svn-id: http://v8.googlecode.com/svn/trunk@10011 ce2b1a6d-e550-0410-aec6-3dcde31c8c00