zstd: 1.4.8 -> 1.4.9

Fixes CVE-2021-24032.

pkgs/tools/compression/zstd/default.nix

@@ -7,13 +7,13 @@
 
 stdenv.mkDerivation rec {
   pname = "zstd";
-  version = "1.4.8";
+  version = "1.4.9";
 
   src = fetchFromGitHub {
     owner = "facebook";
     repo = "zstd";
     rev = "v${version}";
-    sha256 = "018zgigp5xlrb4mgshgrvns0cfbhhcg89cifbjj4rv6s3n9riphw";
+    sha256 = "18alxnym54gswsmsr5ra82q4k1q5fyzsyx0jykb2sk2nkpvx7334";
   };
 
   nativeBuildInputs = [ cmake ]
@@ -21,6 +21,8 @@ stdenv.mkDerivation rec {
   buildInputs = lib.optional stdenv.hostPlatform.isUnix bash;
 
   patches = [
+    # This patches makes sure we do not attempt to use the MD5 implementation
+    # of the host platform when running the tests
     ./playtests-darwin.patch
   ] # This I didn't upstream because if you use posix threads with MinGW it will
     # work fine, and I'm not sure how to write the condition.