fetchCrate: rewrite in terms of fetchzip

pkgs/build-support/rust/fetchcrate.nix

@@ -1,38 +1,15 @@
-{ lib, fetchurl, unzip }:
+{ lib, fetchzip }:
 
 { crateName ? args.pname
 , pname ? null
 , version
-, sha256
-, ... } @ args:
+, ...
+} @ args:
 
 assert pname == null || pname == crateName;
 
-lib.overrideDerivation (fetchurl ({
-
+fetchzip ({
   name = "${crateName}-${version}.tar.gz";
   url = "https://crates.io/api/v1/crates/${crateName}/${version}/download";
-  recursiveHash = true;
-
-  downloadToTemp = true;
-
-  postFetch =
-    ''
-      export PATH=${unzip}/bin:$PATH
-
-      unpackDir="$TMPDIR/unpack"
-      mkdir "$unpackDir"
-      cd "$unpackDir"
-
-      renamed="$TMPDIR/${crateName}-${version}.tar.gz"
-      mv "$downloadedFile" "$renamed"
-      unpackFile "$renamed"
-      fn=$(cd "$unpackDir" && echo *)
-      if [ -f "$unpackDir/$fn" ]; then
-        mkdir $out
-      fi
-      mv "$unpackDir/$fn" "$out"
-    '';
-} // removeAttrs args [ "crateName" "pname" "version" ]))
-# Hackety-hack: we actually need unzip hooks, too
-(x: {nativeBuildInputs = x.nativeBuildInputs++ [unzip];})
+  extension = "tar.gz";
+} // removeAttrs args [ "crateName" "pname" "version" ])