fix macOS build (following Projucer changes made in Windows, which removed /Applications/JUCE/modules from its headers). move JUCE headers under source control, so that Windows and macOS can both build against same version of JUCE. remove AUv3 target (I think it's an iOS thing, so it will never work with this macOS fluidsynth dylib).

modules/juce_gui_basics/native/juce_linux_X11.h

@@ -0,0 +1,142 @@
+/*
+  ==============================================================================
+
+   This file is part of the JUCE library.
+   Copyright (c) 2017 - ROLI Ltd.
+
+   JUCE is an open source library subject to commercial or open-source
+   licensing.
+
+   By using JUCE, you agree to the terms of both the JUCE 5 End-User License
+   Agreement and JUCE 5 Privacy Policy (both updated and effective as of the
+   27th April 2017).
+
+   End User License Agreement: www.juce.com/juce-5-licence
+   Privacy Policy: www.juce.com/juce-5-privacy-policy
+
+   Or: You may also use this code under the terms of the GPL v3 (see
+   www.gnu.org/licenses).
+
+   JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
+   EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
+   DISCLAIMED.
+
+  ==============================================================================
+*/
+
+struct _XDisplay;
+
+namespace juce
+{
+
+typedef ::_XDisplay* XDisplay;
+
+typedef unsigned long AtomType;
+typedef unsigned long WindowType;
+
+
+//==============================================================================
+class XWindowSystem :  public DeletedAtShutdown
+{
+public:
+    XDisplay displayRef() noexcept;
+    XDisplay displayUnref() noexcept;
+
+    JUCE_DECLARE_SINGLETON (XWindowSystem, false)
+
+private:
+    XDisplay display = {};
+    Atomic<int> displayCount;
+
+    XWindowSystem() noexcept;
+    ~XWindowSystem() noexcept;
+
+    void initialiseXDisplay() noexcept;
+    void destroyXDisplay() noexcept;
+};
+
+//==============================================================================
+/** Creates and holds a reference to the X display.
+
+    @tags{GUI}
+*/
+struct ScopedXDisplay
+{
+    ScopedXDisplay();
+    ~ScopedXDisplay();
+
+    const XDisplay display;
+};
+
+//==============================================================================
+/** A handy class that uses XLockDisplay and XUnlockDisplay to lock the X server
+    using RAII (Only available in Linux!).
+
+    @tags{GUI}
+*/
+class ScopedXLock
+{
+public:
+    /** Creating a ScopedXLock object locks the X display.
+        This uses XLockDisplay() to grab the display that JUCE is using.
+    */
+    ScopedXLock (XDisplay);
+
+    /** Deleting a ScopedXLock object unlocks the X display.
+        This calls XUnlockDisplay() to release the lock.
+    */
+    ~ScopedXLock();
+
+private:
+    // defined in juce_linux_X11.h
+    XDisplay display;
+};
+
+//==============================================================================
+struct Atoms
+{
+    Atoms (XDisplay);
+
+    enum ProtocolItems
+    {
+        TAKE_FOCUS = 0,
+        DELETE_WINDOW = 1,
+        PING = 2
+    };
+
+    AtomType protocols, protocolList[3], changeState, state, userTime,
+             activeWin, pid, windowType, windowState,
+             XdndAware, XdndEnter, XdndLeave, XdndPosition, XdndStatus,
+             XdndDrop, XdndFinished, XdndSelection, XdndTypeList, XdndActionList,
+             XdndActionDescription, XdndActionCopy, XdndActionPrivate,
+             XembedMsgType, XembedInfo,
+             allowedActions[5],
+             allowedMimeTypes[4];
+
+    static const unsigned long DndVersion;
+
+    static AtomType getIfExists (XDisplay, const char* name);
+    static AtomType getCreating (XDisplay, const char* name);
+
+    static String getName (XDisplay, AtomType);
+
+    static bool isMimeTypeFile (XDisplay, AtomType);
+};
+
+//==============================================================================
+struct GetXProperty
+{
+    GetXProperty (XDisplay, WindowType, AtomType,
+                  long offset, long length, bool shouldDelete,
+                  AtomType requestedType);
+
+    ~GetXProperty();
+
+    bool success;
+    unsigned char* data = nullptr;
+    unsigned long numItems, bytesLeft;
+    AtomType actualType;
+    int actualFormat;
+};
+
+} // namespace juce