Add support for mill

Signed-off-by: Edward Wang <edward.c.wang@compdigitec.com>

build.sc

@@ -0,0 +1,51 @@
+// Works with mill 0.6.0
+import mill._, scalalib._
+import coursier.MavenRepository
+
+/**
+ * Scala 2.12 module that is source-compatible with 2.11.
+ * This is due to Chisel's use of structural types. See
+ * https://github.com/freechipsproject/chisel3/issues/606
+ */
+trait HasXsource211 extends ScalaModule {
+  override def scalacOptions = T {
+    super.scalacOptions() ++ Seq(
+      "-deprecation",
+      "-unchecked",
+      "-Xsource:2.11"
+    )
+  }
+}
+
+trait HasChisel3 extends ScalaModule {
+  override def ivyDeps = Agg(
+    ivy"edu.berkeley.cs::chisel3:3.2.+"
+ )
+}
+
+trait HasChiselTests extends CrossSbtModule  {
+  object test extends Tests {
+    override def ivyDeps = Agg(
+      ivy"org.scalatest::scalatest:3.0.4",
+      ivy"edu.berkeley.cs::chisel-iotesters:1.2+",
+      ivy"edu.berkeley.cs::chiseltest:0.2-SNAPSHOT"
+    )
+    def repositories = super.repositories ++ Seq(
+      MavenRepository("https://oss.sonatype.org/content/repositories/snapshots")
+    )
+    def testFrameworks = Seq("org.scalatest.tools.Framework")
+  }
+}
+
+trait HasMacroParadise extends ScalaModule {
+  // Enable macro paradise for @chiselName et al
+  val macroPlugins = Agg(ivy"org.scalamacros:::paradise:2.1.0")
+  def scalacPluginIvyDeps = macroPlugins
+  def compileIvyDeps = macroPlugins
+}
+
+object chiselwatt extends CrossSbtModule with HasChisel3 with HasChiselTests with HasXsource211 with HasMacroParadise {
+  override def millSourcePath = super.millSourcePath
+  def crossScalaVersion = "2.12.10"
+}
+