[all-commits] [llvm/llvm-project] 04fce1: [libc++] Fix the build with GCC < 10

[Louis Dionne via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 04fce1515b7ae2fcf7986d8578c18cfd559c68b2
      https://github.com/llvm/llvm-project/commit/04fce1515b7ae2fcf7986d8578c18cfd559c68b2
  Author: Louis Dionne <ldionne at apple.com>
  Date:   2020-10-02 (Fri, 02 Oct 2020)

  Changed paths:
    M libcxx/include/type_traits
    M libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_constructible.pass.cpp

  Log Message:
  -----------
  [libc++] Fix the build with GCC < 10

For now, we still need to support older GCCs, so work around the lack of
__is_constructible on older GCCs.