commit 7ebe239292cf91df5f383ca7ce2491a69aa4f41d
author Petr Hosek <phosek@google.com> Mon Sep 28 16:12:48 2020 -0700
committer Copybara-Service <copybara-worker@google.com> Thu Oct 29 17:48:40 2020 -0700
tree c956279d6d796a1b000143e6af3a7f2393f1f958
parent 62b8b4a49e233e906bcb4c16608e04044f3e216a

[CMake] Use -isystem flag to access libc++ headers

This is a partial revert of D62155. Rather than copying libc++ headers
into the build directory to be later overwritten by the final headers,
use -isystem flag to access libc++ headers during CMake checks. This
should address the occasional flake we've seen, especially on Windows
builders where CMake fails to overwrite __config with the final version.

Differential Revision: https://reviews.llvm.org/D88454

GitOrigin-RevId: 8d26760a95bae34aa5c1161a1c2ab8c1cdaa10a1