VST2: Use 16 channels of midi in VST2 wrapper

modules/juce_audio_plugin_client/VST/juce_VST_Wrapper.cpp

@@ -1171,6 +1171,8 @@ public:
             case plugInOpcodeGetSpeakerArrangement:       return handleGetSpeakerConfiguration (args);
             case plugInOpcodeSetNumberOfSamplesToProcess: return handleSetNumberOfSamplesToProcess (args);
             case plugInOpcodeSetSampleFloatType:          return handleSetSampleFloatType (args);
+            case pluginOpcodeGetNumMidiInputChannels:     return handleGetNumMidiInputChannels();
+            case pluginOpcodeGetNumMidiOutputChannels:    return handleGetNumMidiOutputChannels();
             default:                                      return 0;
         }
     }
@@ -2010,6 +2012,25 @@ private:
         return 0;
     }
 
+    //==============================================================================
+    pointer_sized_int handleGetNumMidiInputChannels()
+    {
+       #if JucePlugin_WantsMidiInput || JucePlugin_IsMidiEffect
+        return 16;
+       #else
+        return 0;
+       #endif
+    }
+
+    pointer_sized_int handleGetNumMidiOutputChannels()
+    {
+       #if JucePlugin_ProducesMidiOutput || JucePlugin_IsMidiEffect
+        return 16;
+       #else
+        return 0;
+       #endif
+    }
+
     //==============================================================================
     JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (JuceVSTWrapper)
 };

modules/juce_audio_processors/format_types/juce_VSTInterface.h

@@ -143,7 +143,9 @@ enum VstHostToPlugInOpcodes
     plugInOpcodeStopProcess,
     plugInOpcodeSetNumberOfSamplesToProcess,
     plugInOpcodeSetSampleFloatType = plugInOpcodeSetNumberOfSamplesToProcess + 4,
-    plugInOpcodeMaximum = plugInOpcodeSetSampleFloatType
+    pluginOpcodeGetNumMidiInputChannels,
+    pluginOpcodeGetNumMidiOutputChannels,
+    plugInOpcodeMaximum = pluginOpcodeGetNumMidiOutputChannels
 };