Remove our fork of forkjoin. Java 8 bundles it.

Provide deprecated compatibility stubs for the types and static members,
which forward as follows:

```
scala.concurrent.forkjoin.ForkJoinPool         => java.util.concurrent.ForkJoinPool
scala.concurrent.forkjoin.ForkJoinTask         => java.util.concurrent.ForkJoinTask
scala.concurrent.forkjoin.ForkJoinWorkerThread => java.util.concurrent.ForkJoinWorkerThread
scala.concurrent.forkjoin.LinkedTransferQueue  => java.util.concurrent.LinkedTransferQueue
scala.concurrent.forkjoin.RecursiveAction      => java.util.concurrent.RecursiveAction
scala.concurrent.forkjoin.RecursiveTask        => java.util.concurrent.RecursiveTask
scala.concurrent.forkjoin.ThreadLocalRandom    => java.util.concurrent.ThreadLocalRandom
```

To prepare for Java 9, the Scala library does not itself use `sun.misc.Unsafe`.
However, for now, it provide a convenience accessor for it
via `scala.concurrent.util.Unsafe`. This (deprecated) class will
be removed as soon as the eco-system drops its use
(akka-actor, I'm looking at you).

Author: adriaanm

build.sbt

@@ -156,7 +156,6 @@ lazy val library = configureAsSubproject(project)
       Seq("-doc-no-compile", libraryAuxDir.toString)
     },
     includeFilter in unmanagedResources in Compile := libIncludes)
-  .dependsOn (forkjoin)
 
 lazy val reflect = configureAsSubproject(project)
   .settings(generatePropertiesFileSettings: _*)
@@ -213,8 +212,6 @@ lazy val scaladoc = configureAsSubproject(project)
 lazy val scalap = configureAsSubproject(project).
   dependsOn(compiler)
 
-lazy val forkjoin = configureAsForkOfJavaProject(project)
-
 lazy val partestExtras = configureAsSubproject(Project("partest-extras", file(".") / "src" / "partest-extras"))
   .dependsOn(repl)
   .settings(clearSourceAndResourceDirectories: _*)
@@ -283,7 +280,7 @@ lazy val test = project.
   )
 
 lazy val root = (project in file(".")).
-  aggregate(library, forkjoin, reflect, compiler, interactive, repl,
+  aggregate(library, reflect, compiler, interactive, repl,
     scaladoc, scalap, partestExtras, junit).settings(
     sources in Compile := Seq.empty,
     onLoadMessage := """|*** Welcome to the sbt build definition for Scala! ***
@@ -312,27 +309,6 @@ def configureAsSubproject(project: Project): Project = {
   (project in base).settings(scalaSubprojectSettings: _*)
 }
 
-/**
- * Configuration for subprojects that are forks of some Java projects
- * we depend on. At the moment there's just forkjoin.
- *
- * We do not publish artifacts for those projects but we package their
- * binaries in a jar of other project (compiler or library).
- *
- * For that reason we disable docs generation, packaging and publishing.
- */
-def configureAsForkOfJavaProject(project: Project): Project = {
-  val base = file(".") / "src" / project.id
-  (project in base).
-    settings(commonSettings: _*).
-    settings(disableDocsAndPublishingTasks: _*).
-    settings(
-      sourceDirectory in Compile := baseDirectory.value,
-      javaSource in Compile := (sourceDirectory in Compile).value,
-      sources in Compile in doc := Seq.empty,
-      classDirectory in Compile := buildDirectory.value / "libs/classes" / thisProject.value.id
-    )
-}
 
 lazy val buildDirectory = settingKey[File]("The directory where all build products go. By default ./build")
 lazy val copyrightString = settingKey[String]("Copyright string.")

build.xml

@@ -165,7 +165,6 @@ TODO:
   <property name="build.dir"               value="${basedir}/build"/>
   <property name="build-deps.dir"          value="${build.dir}/deps"/>
   <property name="build-libs.dir"          value="${build.dir}/libs"/>
-  <property name="build-forkjoin.dir"      value="${build-libs.dir}"/>
   <property name="build-locker.dir"        value="${build.dir}/locker"/>
   <property name="build-quick.dir"         value="${build.dir}/quick"/>
   <property name="build-pack.dir"          value="${build.dir}/pack"/>
@@ -570,9 +569,6 @@ TODO:
       </propertyfile>
     </then></if>
 
-    <path id="forkjoin.classpath" path="${build-forkjoin.dir}/classes/forkjoin"/>
-    <property name="forkjoin-classes" refid="forkjoin.classpath"/>
-
     <!-- the following properties fully define staged-docs, staged-pack, make-bundle, copy-bundle and mvn-package for each of the projects -->
     <property name="library.description"           value="Scala Standard Library"/>
     <property name="library.docroot"               value="rootdoc.txt"/>
@@ -627,7 +623,7 @@ TODO:
     <property name="partest-extras.description"    value="Scala Compiler Testing Tool (compiler-specific extras)"/>
     <property name="partest-javaagent.description" value="Scala Compiler Testing Tool (compiler-specific java agent)"/>
 
-    <!-- projects without project-specific options: forkjoin, manual, bin, repl -->
+    <!-- projects without project-specific options: manual, bin, repl -->
     <for list="compiler,interactive,scaladoc,library,parser-combinators,partest,partest-extras,partest-javaagent,reflect,scalap,swing,xml,repl-jline" param="project">
       <sequential>
         <!-- description is mandatory -->
@@ -685,7 +681,6 @@ TODO:
     <!-- LOCKER -->
     <path id="locker.library.build.path">
       <pathelement location="${build-locker.dir}/classes/library"/>
-      <path refid="forkjoin.classpath"/>
       <path refid="aux.libs"/>
     </path>
 
@@ -706,7 +701,6 @@ TODO:
     <!-- QUICK -->
     <path id="quick.library.build.path">
       <pathelement location="${build-quick.dir}/classes/library"/>
-      <path refid="forkjoin.classpath"/>
       <path refid="aux.libs"/>
     </path>
 
@@ -781,7 +775,6 @@ TODO:
       <pathelement location="${reflect.jar}"/>
       <pathelement location="${compiler.jar}"/>
       <pathelement location="${ant.jar}"/>
-      <path refid="forkjoin.classpath"/>
       <path refid="aux.libs"/>
     </path>
 
@@ -799,7 +792,6 @@ TODO:
 
     <path id="pack.library.files">
       <fileset dir="${build-quick.dir}/classes/library"/>
-      <fileset dir="${forkjoin-classes}"/>
     </path>
 
     <path id="pack.repl-jline.files">    <fileset dir="${build-quick.dir}/classes/repl-jline"/> </path>
@@ -829,7 +821,6 @@ TODO:
     <!-- STRAP -->
     <path id="strap.library.build.path">
       <pathelement location="${build-strap.dir}/classes/library"/>
-      <path refid="forkjoin.classpath"/>
       <path refid="aux.libs"/>
     </path>
 
@@ -958,7 +949,6 @@ TODO:
       <pathelement location="${build-osgi.dir}/org.scala-lang.scala-reflect.jar"/>
       <pathelement location="${build-osgi.dir}/org.scala-lang.scala-compiler.jar"/>
       <path refid="pax.exam.classpath"/>
-      <path refid="forkjoin.classpath"/>
     </path>
 
     <path id="test.osgi.compiler.build.path.felix">
@@ -1029,8 +1019,6 @@ TODO:
                                   LOCAL DEPENDENCIES
 ============================================================================ -->
 
-  <target name="forkjoin.done" depends="init"> <simple-javac project="forkjoin" args="-XDignore.symbol.file" jar="no"/></target>
-
   <!-- For local development only. We only allow released versions of Scala for STARR.
     This builds quick (core only) and publishes it with a generated version number,
     saving it as starr.version in build.properties, so this compiler will be used as STARR in your next build
@@ -1051,7 +1039,7 @@ TODO:
 <!-- ===========================================================================
                                   LOCAL REFERENCE BUILD (LOCKER)
 ============================================================================ -->
-  <target name="locker.start"  depends="forkjoin.done">
+  <target name="locker.start"  depends="init">
     <condition property="locker.locked"><available file="${build-locker.dir}/locker.locked"/></condition></target>
 
   <target name="locker.lib"    depends="locker.start"     unless="locker.locked">
@@ -1137,7 +1125,7 @@ TODO:
 <!-- ===========================================================================
                                   PACKED QUICK BUILD (PACK)
 ============================================================================ -->
-  <target name="pack.lib"    depends="quick.lib, forkjoin.done"> <staged-pack project="library"/></target>
+  <target name="pack.lib"    depends="quick.lib"> <staged-pack project="library"/></target>
 
   <target name="pack.reflect" depends="quick.reflect"> <staged-pack project="reflect"/> </target>