llvm/utils/gn/secondary/libcxx/config.gni

declare_args() {
  # libc++ ABI version. Either 1 (default) or 2 (unstable).
  libcxx_abi_version = 1

  # libc++ inline ABI namespace. Defaults to __n, where n is the ABI version.
  libcxx_abi_namespace = ""
}