Extract build configuration into a separate header and move it to the base lib

Extract build configuration into a separate header and move it to the base lib

With this, change, atomicops, once, and lazy instance are no longer dependant
on v8 core. I'll move them in a follow-up change to the libbase as well.

BUG=none
R=jkummerow@chromium.org
LOG=n

Review URL: https://codereview.chromium.org/303463005

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@21546 ce2b1a6d-e550-0410-aec6-3dcde31c8c00