Some mingw compile fixes.

modules/juce_audio_plugin_client/VST/juce_VST_Wrapper.cpp

@@ -41,6 +41,14 @@
  #undef STRICT
  #define STRICT 1
  #include <windows.h>
+
+ #ifdef __MINGW32__
+  struct MOUSEHOOKSTRUCTEX
+  {
+     MOUSEHOOKSTRUCT _unnamed;
+     DWORD mouseData;
+  };
+ #endif
 #elif defined (LINUX)
  #include <X11/Xlib.h>
  #include <X11/Xutil.h>

modules/juce_audio_processors/format_types/juce_VSTPluginFormat.cpp

@@ -65,6 +65,10 @@
 #include "juce_VSTMidiEventList.h"
 
 #if JUCE_MINGW
+ #ifndef WM_APPCOMMAND
+  #define WM_APPCOMMAND 0x0319
+ #endif
+
  extern "C" void _fpreset();
  extern "C" void _clearfp();
 #elif ! JUCE_WINDOWS