cargo: Remove setupHook

Instead, move that code into buildRustPackage.

The setup hook was only doing part of the work anyway, and having it in
a separate place was obscuring what was really going on.

pkgs/build-support/rust/default.nix

@@ -19,6 +19,12 @@ in stdenv.mkDerivation (args // {
   configurePhase = args.configurePhase or "true";
 
   postUnpack = ''
+    echo "Using cargo deps from $cargoDeps"
+    cp -r $cargoDeps deps
+    chmod +w deps -R
+
+    export CARGO_HOME=$(realpath deps)
+
     echo "Using rust registry from $rustRegistry"
     (
         cd $sourceRoot

pkgs/development/tools/build-managers/cargo/common.nix

@@ -29,6 +29,4 @@
     license = [ licenses.mit licenses.asl20 ];
     platforms = platforms.linux;
   };
-
-  setupHook = ./setup-hook.sh;
 }

pkgs/development/tools/build-managers/cargo/default.nix

@@ -6,7 +6,7 @@ with ((import ./common.nix) { inherit stdenv; version = "2015-04-14"; });
 with rustPlatform;
 
 buildRustPackage rec {
-  inherit name version meta setupHook;
+  inherit name version meta;
 
   src = fetchgit {
     url = "https://github.com/rust-lang/cargo.git";

pkgs/development/tools/build-managers/cargo/setup-hook.sh

@@ -1,6 +0,0 @@
-if [[ -n "$cargoDeps" ]]; then
-   echo "Using cargo deps from $cargoDeps"
-   cp -r $cargoDeps deps
-   chmod +w deps -R
-   export CARGO_HOME=$(realpath deps)
-fi

pkgs/development/tools/build-managers/cargo/snapshot.nix

@@ -20,7 +20,7 @@ let snapshotHash = if stdenv.system == "i686-linux"
 in
 
 stdenv.mkDerivation {
-  inherit name version meta setupHook;
+  inherit name version meta;
 
   src = fetchurl {
     url = "https://static-rust-lang-org.s3.amazonaws.com/cargo-dist/${snapshotDate}/${snapshotName}";