rustc: avoid corrupting or1k crates

artiq/pkgs/rust/default.nix

@@ -3,6 +3,7 @@
 , targetToolchains ? []
 , targetPatches ? []
 , fetchFromGitHub
+, runCommand
 }:
 
 let
@@ -61,20 +62,9 @@ let
     '';
   };
 in
- stdenv.mkDerivation {
-    name = "rustc";
-    src = ./.;
-    installPhase = ''
-      mkdir $out
-      mkdir -p $out/lib/rustlib/or1k-unknown-none/lib/
-      cp -r ${or1k-crates}/* $out/lib/rustlib/or1k-unknown-none/lib/
-      cp -r ${rustc_internal}/* $out
-    '';
-    meta = with stdenv.lib; {
-      homepage = https://www.rust-lang.org/;
-      description = "A safe, concurrent, practical language";
-      maintainers = with maintainers; [ sb0 ];
-      license = [ licenses.mit licenses.asl20 ];
-      platforms = platforms.linux ++ platforms.darwin;
-    };
-  }
+ runCommand "rustc" {}
+    ''
+    mkdir -p $out/lib/rustlib/or1k-unknown-none/lib/
+    cp -r ${or1k-crates}/* $out/lib/rustlib/or1k-unknown-none/lib/
+    cp -r ${rustc_internal}/* $out
+    ''