dexed: Fix build on Darwin

pkgs/applications/audio/dexed/default.nix

···
 , freetype
 , alsa-lib
 , libjack2
+, Accelerate
 , Cocoa
 , WebKit
 , MetalKit
···
     alsa-lib
     libjack2
   ] ++ lib.optionals stdenv.hostPlatform.isDarwin [
+    Accelerate
     Cocoa
     WebKit
     MetalKit

pkgs/top-level/all-packages.nix

···
   denemo = callPackage ../applications/audio/denemo { };
 
   dexed = darwin.apple_sdk_11_0.callPackage ../applications/audio/dexed {
-    inherit (darwin.apple_sdk_11_0.frameworks) Cocoa WebKit MetalKit DiscRecording CoreAudioKit;
+    inherit (darwin.apple_sdk_11_0.frameworks) Accelerate Cocoa WebKit MetalKit DiscRecording CoreAudioKit;
     inherit (darwin.apple_sdk_11_0.libs) simd;
   };