Revert new OS and CC detection and related changes since r15923.

Revert "Attempt to fix leftover test breakage on Mac."
Revert "Fix d8 build error when V8_SHARED is unset on Linux."
Revert "Fix V8_GNUC_PREREQ macro."
Revert "Fix typo."
Revert "Implement correct OS and CC detection."

TBR=svenpanne@chromium.org,danno@chromium.org

Review URL: https://codereview.chromium.org/21022003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@15932 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Fix: Need to remove function type feedback between stress stages in
release build

BUG=
R=verwaest@chromium.org

Review URL: https://codereview.chromium.org/20987005

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@15933 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Fix IsDeletable() for HStringAdd, HStringCharCodeAt, HStringCharFromCode.

BUG=
R=mstarzinger@chromium.org, svenpanne@chromium.org

Review URL: https://codereview.chromium.org/20241005

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@15934 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Added unit tests for the slightly confusing Boolean/BooleanObject API.

Just for documenting the status quo. As discussed offline, we should
probably rename/deprecate a few things:

  NumberObject::NumberValue() => NumberObject::ValueOf()
  BooleanObject::BooleanValue() => BooleanObject::ValueOf()
  StringObject::StringValue => StringObject::ValueOf()

R=mstarzinger@chromium.org

Review URL: https://codereview.chromium.org/21013003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@15935 ce2b1a6d-e550-0410-aec6-3dcde31c8c00