Extract common macros and start a base library

BUG=v8:3015
R=svenpanne@chromium.org
LOG=n

Review URL: https://codereview.chromium.org/249183003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@20905 ce2b1a6d-e550-0410-aec6-3dcde31c8c00