Remove setting a default value for use_custom_libcxx Update the .gn to remove forcing use_custom_libcxx = false. Instead, let //build/config/c++/c++.gni determine the value, which should better match Chromium. In particular, this helps with Abseil integration by supporting Windows component builds by better matching the contents of the .def files. Bug: angleproject:4873 Test: CQ Change-Id: If8c064f16459292bfb95113a4d78e14e8923f86f Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2414739 Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Tim Van Patten <timvp@google.com>