GradleでScala2.11のコンパイルをするには

Gradleを2.xにしないと、ワケワカなエラーが出ます。

/tmp/sbt_234ad403/CompilerInterface.scala:240: error: recursive method rootLoader needs result type
            override def rootLoader = if(resident) newPackageLoaderCompat(rootLoader)(compiler.classPath) else super.rootLoader
                                                                                      ^
/tmp/sbt_234ad403/CompilerInterface.scala:240: error: value rootLoader is not a member of scala.tools.nsc.backend.JavaPlatform
            override def rootLoader = if(resident) newPackageLoaderCompat(rootLoader)(compiler.classPath) else super.rootLoader
                                                                                                                                 ^
/tmp/sbt_234ad403/CompilerInterface.scala:261: error: value RootClass is not a member of object xsbt.CachedCompiler0.compiler.definitions
                            reSyncCompat(definitions.RootClass, Some(classPath), Some(oldEntry), Some(newEntry))
                                                                                 ^
/tmp/sbt_234ad403/CompilerInterface.scala:337: error: value RootClass is not a member of object xsbt.CachedCompiler0.compiler.definitions
            pkg == definitions.RootClass ||
                                           ^
/tmp/sbt_234ad403/CompilerInterface.scala:286: error: value EmptyPackageClass is not a member of object xsbt.CachedCompiler0.compiler.definitions
                    invalidateOrRemove(definitions.EmptyPackageClass.asInstanceOf[ClassSymbol])