Centralize C++ compiler flags in rn_defs.bzl
Centralize C++ compiler flags in rn_defs.bzl

Summary:
Centralize C++ compiler flags in rn_defs.bzl.

There is really no reason for these Cxx libraries to specify their own compiler flags: nearly 100% of them are identical, and the copypasta makes it difficult to make repo-wide changes (like upgrading C++ versions, etc).

This is now causing build failures until everything is migrated properly, and there are two flags (enable_rtti and enable_exceptions) that MUST have the same value and can be configured per-module, as needed.

Changelog: [Internal]

Reviewed By: mdvacca

Differential Revision: D31631767

fbshipit-source-id: 84f0441eb0ad09219e97d13babe0707d25f08472

facebook/react-native,facebook/react-native,javache/react-native,janicduplessis/react-native,facebook/react-native,javache/react-native,janicduplessis/react-native,facebook/react-native,javache/react-native,facebook/react-native,janicduplessis/react-native,javache/react-native,javache/react-native,javache/react-native,facebook/react-native,facebook/react-native,javache/react-native,janicduplessis/react-native,facebook/react-native,janicduplessis/react-native,janicduplessis/react-native,facebook/react-native,javache/react-native,janicduplessis/react-native,janicduplessis/react-native,javache/react-native