zfs: Cherry-pick upstream commit ef977fce6636 to fix macOS/arm64 bootstrap

zfs: Cherry-pick upstream commit ef977fce6636 to fix macOS/arm64 bootstrap

Upstream commit message:

  Support running FreeBSD buildworld on Arm-based macOS hosts

  Arm-based Macs are like FreeBSD and provide a full 64-bit stat from the
  start, so have no stat64 variants. Thus, define stat64 and fstat64 as
  aliases for the normal versions.

  Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
  Signed-off-by: Jessica Clarke <jrtc27@jrtc27.com>
  Closes #11771

(cherry picked from commit 3a314eb5bb444ec019457e5aefaabb656fcb3d54)