openrgb: add withPlugins

pkgs/applications/misc/openrgb/default.nix

@@ -1,4 +1,4 @@
-{ lib, stdenv, fetchFromGitLab, qmake, wrapQtAppsHook, libusb1, hidapi, pkg-config, coreutils, mbedtls_2, qtbase, qttools }:
+{ lib, stdenv, fetchFromGitLab, qmake, wrapQtAppsHook, libusb1, hidapi, pkg-config, coreutils, mbedtls_2, qtbase, qttools, symlinkJoin, openrgb }:
 
 stdenv.mkDerivation rec {
   pname = "openrgb";
@@ -25,6 +25,29 @@ stdenv.mkDerivation rec {
     HOME=$TMPDIR $out/bin/openrgb --help > /dev/null
   '';
 
+  passthru.withPlugins = plugins:
+    let pluginsDir = symlinkJoin {
+      name = "openrgb-plugins";
+      paths = plugins;
+      # Remove all library version symlinks except one,
+      # or they will result in duplicates in the UI.
+      # We leave the one pointing to the actual library, usually the most
+      # qualified one (eg. libOpenRGBHardwareSyncPlugin.so.1.0.0).
+      postBuild = ''
+        for f in $out/lib/*; do
+          if [ "$(dirname $(readlink "$f"))" == "." ]; then
+            rm "$f"
+          fi
+        done
+      '';
+    };
+    in openrgb.overrideAttrs (old: {
+      qmakeFlags = old.qmakeFlags or [] ++ [
+        # Welcome to Escape Hell, we have backslashes
+        ''DEFINES+=OPENRGB_EXTRA_PLUGIN_DIRECTORY=\\\""${lib.escape ["\\" "\"" " "] (toString pluginsDir)}/lib\\\""''
+      ];
+    });
+
   meta = with lib; {
     description = "Open source RGB lighting control";
     homepage = "https://gitlab.com/CalcProgrammer1/OpenRGB";