haskell: use GHCJS to build Setup.hs for GHCJS packages

Closes https://github.com/NixOS/nixpkgs/pull/23614.

pkgs/development/compilers/ghcjs/stage2.nix

@@ -327,6 +327,7 @@
         version = "1.22.8.0";
         src = "${ghcjsBoot}/boot/cabal/Cabal";
         doCheck = false;
+        hyperlinkSource = false;
         libraryHaskellDepends = [
           array base binary bytestring containers deepseq directory filepath
           pretty process time unix

pkgs/development/haskell-modules/configuration-ghcjs.nix

@@ -53,6 +53,14 @@ self: super:
   terminfo = self.terminfo_0_4_0_2;
   xhtml = self.xhtml_3000_2_1;
 
+  # Cabal isn't part of the stage1 packages which form the default package-db
+  # that GHCJS provides.
+  # Almost all packages require Cabal to build their Setup.hs,
+  # but usually they don't declare it explicitly as they don't need to for normal GHC.
+  # To account for that we add Cabal by default.
+  mkDerivation = args:
+    if args.pname == "Cabal" then super.mkDerivation args else super.mkDerivation (args //
+      { setupHaskellDepends = (args.setupHaskellDepends or []) ++ [ self.Cabal ]; });
 
 ## OTHER PACKAGES
 

pkgs/development/haskell-modules/default.nix

@@ -15,6 +15,7 @@ let
       mkDerivationImpl = pkgs.callPackage ./generic-builder.nix {
         inherit stdenv;
         inherit (pkgs) fetchurl pkgconfig glibcLocales coreutils gnugrep gnused;
+        nodejs = pkgs.nodejs-slim;
         jailbreak-cabal = if (self.ghc.cross or null) != null
           then self.ghc.bootPkgs.jailbreak-cabal
           else self.jailbreak-cabal;

pkgs/development/haskell-modules/generic-builder.nix

@@ -1,5 +1,5 @@
 { stdenv, fetchurl, ghc, pkgconfig, glibcLocales, coreutils, gnugrep, gnused
-, jailbreak-cabal, hscolour, cpphs
+, jailbreak-cabal, hscolour, cpphs, nodejs
 }: let isCross = (ghc.cross or null) != null; in
 
 { pname
@@ -133,6 +133,7 @@ let
 
   setupCompileFlags = [
     (optionalString (!coreSetup) "-${packageDbFlag}=$packageConfDir")
+    (optionalString isGhcjs "-build-runner")
     (optionalString (isGhcjs || isHaLVM || versionOlder "7.8" ghc.version) "-j$NIX_BUILD_CORES")
     # https://github.com/haskell/cabal/issues/2398
     (optionalString (versionOlder "7.10" ghc.version && !isHaLVM) "-threaded")
@@ -157,7 +158,7 @@ let
 
   ghcEnv = ghc.withPackages (p: haskellBuildInputs);
 
-  setupBuilder = if isCross || isGhcjs then "${nativeGhc}/bin/ghc" else ghcCommand;
+  setupBuilder = if isCross then "${nativeGhc}/bin/ghc" else ghcCommand;
   setupCommand = "./Setup";
   ghcCommand' = if isGhcjs then "ghcjs" else "ghc";
   crossPrefix = if (ghc.cross or null) != null then "${ghc.cross.config}-" else "";
@@ -294,6 +295,14 @@ stdenv.mkDerivation ({
       local pkgId=$( ${gnused}/bin/sed -n -e 's|^id: ||p' $packageConfFile )
       mv $packageConfFile $packageConfDir/$pkgId.conf
     ''}
+    ${optionalString isGhcjs ''
+      for exeDir in "$out/bin/"*.jsexe; do
+        exe="''${exeDir%.jsexe}"
+        printf '%s\n' '#!${nodejs}/bin/node' > "$exe"
+        cat "$exeDir/all.js" >> "$exe"
+        chmod +x "$exe"
+      done
+    ''}
     ${optionalString doCoverage "mkdir -p $out/share && cp -r dist/hpc $out/share"}
     ${optionalString (enableSharedExecutables && isExecutable && !isGhcjs && stdenv.isDarwin && stdenv.lib.versionOlder ghc.version "7.10") ''
       for exe in "$out/bin/"* ; do

pkgs/development/haskell-modules/lib.nix

@@ -38,6 +38,9 @@ rec {
   addPkgconfigDepend = drv: x: addPkgconfigDepends drv [x];
   addPkgconfigDepends = drv: xs: overrideCabal drv (drv: { pkgconfigDepends = (drv.pkgconfigDepends or []) ++ xs; });
 
+  addSetupDepend = drv: x: addSetupDepends drv [x];
+  addSetupDepends = drv: xs: overrideCabal drv (drv: { setupHaskellDepends = (drv.setupHaskellDepends or []) ++ xs; });
+
   enableCabalFlag = drv: x: appendConfigureFlag (removeConfigureFlag drv "-f-${x}") "-f${x}";
   disableCabalFlag = drv: x: appendConfigureFlag (removeConfigureFlag drv "-f${x}") "-f-${x}";