Enable _LIBCPP_DEBUG in Clang for non-Xcode-based debug builds.

Unlike _GLIBCXX_DEBUG, this is meant to not break the ABI.
The libc++ bundled with Xcode does not contain debug symbols so we need
to disable these checks on Mac/iOS.

Change-Id: Ie4f18e247db9c405b2ce45f388c41dcac8104815
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/297874
Commit-Queue: John Stiles <johnstiles@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
Reviewed-by: Mike Klein <mtklein@google.com>
1 file changed