retroarch: refactor wrapper to use symlinkJoin

pkgs/applications/emulators/retroarch/default.nix

@@ -170,7 +170,6 @@ stdenv.mkDerivation rec {
     mainProgram = "retroarch";
     # FIXME: error while building in macOS:
     # "Undefined symbols for architecture <arch>"
-    # See also retroarch/wrapper.nix that is also broken in macOS
     broken = stdenv.isDarwin;
   };
 }

pkgs/applications/emulators/retroarch/wrapper.nix

@@ -1,41 +1,51 @@
-{ stdenv, lib, makeWrapper, retroarch, cores ? [ ] }:
+{ lib
+, stdenv
+, makeWrapper
+, retroarch
+, symlinkJoin
+, cores ? [ ]
+}:
 
-stdenv.mkDerivation {
-  pname = "retroarch";
-  version = lib.getVersion retroarch;
+let
+  coresPath = lib.lists.unique (map (c: c.libretroCore) cores);
+  wrapperArgs = lib.strings.escapeShellArgs
+    (lib.lists.flatten
+      (map (corePath: [ "--add-flags" "-L ${placeholder "out" + corePath}" ]) coresPath));
+in
+symlinkJoin {
+  name = "retroarch-with-cores-${lib.getVersion retroarch}";
+
+  paths = [ retroarch ] ++ cores;
 
   nativeBuildInputs = [ makeWrapper ];
 
-  buildCommand = ''
-    mkdir -p $out/lib
-    for coreDir in $cores; do
-      ln -s $coreDir/* $out/lib/.
-    done
-
-    ln -s -t $out ${retroarch}/share
-
-    if [ -d ${retroarch}/Applications ]; then
-      ln -s -t $out ${retroarch}/Applications
-    fi
+  passthru = {
+    inherit cores;
+    unwrapped = retroarch;
+  };
 
+  postBuild = ''
+    # remove core specific binaries
+    find $out/bin -name 'retroarch-*' -delete
+    # wrapProgram can't operate on symlinks
+    rm $out/bin/retroarch
     makeWrapper ${retroarch}/bin/retroarch $out/bin/retroarch \
-      --suffix-each LD_LIBRARY_PATH ':' "$cores" \
-      --add-flags "-L $out/lib/" \
+      ${wrapperArgs}
+  '' + lib.optionalString stdenv.isDarwin ''
+    # wrapProgram can't operate on symlinks
+    rm $out/Applications/RetroArch.app/Contents/MacOS/retroarch
+    makeWrapper ${retroarch}/bin/retroarch $out/Applications/RetroArch.app/Contents/MacOS/retroarch \
+      ${wrapperArgs}
   '';
 
-  cores = map (x: x + x.libretroCore) cores;
-  preferLocalBuild = true;
-
   meta = with retroarch.meta; {
     inherit changelog description homepage license maintainers platforms;
     longDescription = ''
       RetroArch is the reference frontend for the libretro API.
-
-      The following cores are included:
-      ${lib.concatStringsSep "\n" (map (x: "  - ${x.name}") cores)}
+    ''
+    + lib.optionalString (cores != [ ]) ''
+      The following cores are included: ${lib.concatStringsSep ", " (map (x: x.core) cores)}
     '';
-    # FIXME: exit with error on macOS:
-    # No Info.plist file in application bundle or no NSPrincipalClass in the Info.plist file, exiting
-    broken = stdenv.isDarwin;
+    mainProgram = "retroarch";
   };
 }