Add support for Dotty projects (#397)

* Abstract over the scala compiler organization

* Support using a locally published compiler

Publishing locally with sbt means publishing ivy-style, which uses
a different naming convention than maven, we now handle both cases.

* Add minimal support for Dotty projects

* Rewrite scalalib.Dep, introduce scalalib.CrossVersion

Instead of Dep being a trait with three cases (Java/Scala/Point), it is
now a case class where the cross field is an instance of the
CrossVersion trait which has three cases (Constant/Binary/Full). This is
more versatile since it allows for non-empty constant suffixes which
will be used to implement withDottyCompat in the next commit. It's
also a cleaner separation of concerns. We also deduplicate various
pieces of codes that computed the artifact name: this is now always handled in
Dep and CrossVersion.

* Add simple way to use Scala 2 deps in a Dotty project

This is similar to the withDottyCompat method in the sbt-dotty plugin.

* Turn off the Dotty test on Java >= 9

1 files changed, 2 insertions, 2 deletions

diff --git a/integration/test/resources/play-json/build.sc b/integration/test/resources/play-json/build.sc
index c60eefba..d4557011 100644
--- a/integration/test/resources/play-json/build.sc
+++ b/integration/test/resources/play-json/build.sc
@@ -61,7 +61,7 @@ abstract class PlayJson(val platformSegment: String) extends PlayJsonModule {
   )
 
   def ivyDeps = Agg(
-    ivy"org.scala-lang:scala-reflect:${scalaVersion()}",
+    ivy"${scalaOrganization()}:scala-reflect:${scalaVersion()}",
     ivy"org.typelevel::macro-compat::1.1.1"
   )
 
@@ -69,7 +69,7 @@ abstract class PlayJson(val platformSegment: String) extends PlayJsonModule {
 
   def compileIvyDeps = Agg(
     macroParadise,
-    ivy"org.scala-lang:scala-compiler:${scalaVersion()}"
+    ivy"${scalaOrganization()}:scala-compiler:${scalaVersion()}"
   )
 
   def scalacPluginIvyDeps = Agg(macroParadise)