tar2ext4: init at 0.8.20

This is a single program that's part of a big Microsoft project.
Everything else looks pretty specialised, and some of it only targets
Windows, so I didn't try packaging anything else.  If we ever do end
up with a need for other software from this project, this derivation
could be extended and renamed, with tar2ext4 becoming an alias.

pkgs/tools/filesystems/tar2ext4/default.nix

@@ -0,0 +1,23 @@
+{ lib, buildGoModule, fetchFromGitHub }:
+
+buildGoModule rec {
+  pname = "tar2ext4";
+  version = "0.8.20";
+
+  src = fetchFromGitHub {
+    owner = "microsoft";
+    repo = "hcsshim";
+    rev = "v${version}";
+    sha256 = "sha256-X7JsUFL9NkNT7ihE5olrqMUP8RnoVC10KLrQeT/OU3o=";
+  };
+
+  sourceRoot = "source/cmd/tar2ext4";
+  vendorSha256 = null;
+
+  meta = with lib; {
+    description = "Convert a tar archive to an ext4 image";
+    maintainers = with maintainers; [ qyliss ];
+    license = licenses.mit;
+    platforms = platforms.all;
+  };
+}

pkgs/top-level/all-packages.nix

@@ -9298,6 +9298,8 @@ with pkgs;
 
   znapzend = callPackage ../tools/backup/znapzend { };
 
+  tar2ext4 = callPackage ../tools/filesystems/tar2ext4 { };
+
   targetcli = callPackage ../os-specific/linux/targetcli { };
 
   target-isns = callPackage ../os-specific/linux/target-isns { };