Merge commit 3537338d1ab9 from llvm git (by Nikolas Klauser):

Merge commit 3537338d1ab9 from llvm git (by Nikolas Klauser):

    [libc++][libunwind] Fixes to allow GCC 13 to compile libunwind/libc++abi/libc++

    These are changes to allow GCC 13 to successfully compile the runtimes stack.

    Reviewed By: ldionne, #libc, #libunwind, MaskRay

    Spies: MaskRay, zibi, SeanP, power-llvm-team, mstorsjo, arichardson, libcxx-commits

    Differential Revision: https://reviews.llvm.org/D151387

Reviewed by:	imp, dim, emaste
Differential Revision:	https://reviews.freebsd.org/D42578

(cherry picked from commit ab43851b0c7bd5f21ade72c3cae3d3ee09eb8891)