zstd: fix darwin patch
zstd: fix darwin patch

Since v1.4.9, another stat command has been added to playTests.sh.
Similar to other uses in this file, it attempts to use BSD syntax on
Darwin/BSD, and must be patched to unconditionally use GNU syntax.

NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs