Fix OSGi headers

- Export all our packages (fixes #224)
- Import the correct standard library version
  (using code from https://github.com/slick/slick/blob/master/project/Osgi.scala)
- No private packages needed

Author: szeiger

build.sbt

@@ -57,6 +57,17 @@ scalaVersionsByJvm in ThisBuild := {
   )
 }
 
+/** Create an OSGi version range for standard Scala versioning
+  * schemes that describes binary compatible versions. */
+def osgiVersionRange(version: String, requireMicro: Boolean = false): String =
+  if(version contains '-') "${@}" // M, RC or SNAPSHOT -> exact version
+  else if(requireMicro) "${range;[===,=+)}" // At least the same micro version
+  else "${range;[==,=+)}" // Any binary compatible version
+
+/** Create an OSGi Import-Package version specification. */
+def osgiImport(pattern: String, version: String, requireMicro: Boolean = false): String =
+  pattern + ";version=\"" + osgiVersionRange(version, requireMicro) + "\""
+
 lazy val compat = MultiScalaCrossProject(JSPlatform, JVMPlatform)(
   "compat",
   _.settings(scalaModuleSettings)
@@ -73,7 +84,14 @@ lazy val compat = MultiScalaCrossProject(JSPlatform, JVMPlatform)(
       }
     )
     .jvmSettings(
-      OsgiKeys.exportPackage := Seq(s"scala.collection.compat.*;version=${version.value}"),
+      OsgiKeys.exportPackage := {
+        if (scalaVersion.value.startsWith("2.13."))
+          Seq(s"scala.collection.compat.*;version=${version.value}")
+        else
+          Seq(s"scala.collection.compat.*;version=${version.value},scala.jdk.*;version=${version.value}")
+      },
+      OsgiKeys.importPackage := Seq(osgiImport("*", scalaBinaryVersion.value)),
+      OsgiKeys.privatePackage := Nil,
       junit
     )
     .jsSettings(