ENV part of the build environment. This is mostly to support Windows
builds in cases where SCons cannot find the correct paths to the
Windows SDK, as these paths cannot be passed through shell envrionment
variables.


git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@87 ce2b1a6d-e550-0410-aec6-3dcde31c8c00