scala-runners: init at unstable-2020-02-02

This is a script to run multiple versions of scala either by version
number or build hash.

pkgs/development/compilers/scala-runners/default.nix

@@ -0,0 +1,31 @@
+{ stdenv, lib, fetchFromGitHub, jre, coursier }:
+
+stdenv.mkDerivation rec {
+  pname = "scala-runners";
+  version = "unstable-2020-02-02";
+
+  src = fetchFromGitHub {
+    repo = pname;
+    owner = "dwijnand";
+    rev = "95e03c9f9de0fe0ab61eeb6dea2a364f9d081d31";
+    sha256 = "0mvlc6fxsh5d6gsyak9n3g98g4r061n8pir37jpiqb7z00m9lfrx";
+  };
+
+  installPhase = ''
+    mkdir -p $out/bin $out/lib
+    sed -ie "s| cs | ${coursier}/bin/coursier |" scala-runner
+    cp scala-runner $out/lib
+    ln -s $out/lib/scala-runner $out/bin/scala
+    ln -s $out/lib/scala-runner $out/bin/scalac
+    ln -s $out/lib/scala-runner $out/bin/scalap
+    ln -s $out/lib/scala-runner $out/bin/scaladoc
+  '';
+
+  meta = with lib; {
+    homepage = "https://github.com/dwijnand/scala-runners";
+    description = "An alternative implementation of the Scala distribution's runners";
+    license = licenses.asl20;
+    platforms = platforms.all;
+    maintainers = with maintainers; [ hrhino ];
+  };
+}

pkgs/top-level/all-packages.nix

@@ -12014,6 +12014,10 @@ in
   scala_2_13 = callPackage ../development/compilers/scala/2.x.nix { majorVersion = "2.13"; jre = jdk8; };
 
   scala = scala_2_13;
+  scala-runners = callPackage ../development/compilers/scala-runners/default.nix {
+    coursier = coursier.override { jre = jdk8; };
+    jre = jdk8;
+  };
 
   metal = callPackage ../development/libraries/metal { };
   metals = callPackage ../development/tools/metals { };