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/layout/juce_StretchableLayoutResizerBar.h

@@ -0,0 +1,106 @@
+/*
+  ==============================================================================
+
+   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.
+
+  ==============================================================================
+*/
+
+namespace juce
+{
+
+//==============================================================================
+/**
+    A component that acts as one of the vertical or horizontal bars you see being
+    used to resize panels in a window.
+
+    One of these acts with a StretchableLayoutManager to resize the other components.
+
+    @see StretchableLayoutManager
+
+    @tags{GUI}
+*/
+class JUCE_API  StretchableLayoutResizerBar  : public Component
+{
+public:
+    //==============================================================================
+    /** Creates a resizer bar for use on a specified layout.
+
+        @param layoutToUse          the layout that will be affected when this bar
+                                    is dragged
+        @param itemIndexInLayout    the item index in the layout that corresponds to
+                                    this bar component. You'll need to set up the item
+                                    properties in a suitable way for a divider bar, e.g.
+                                    for an 8-pixel wide bar which, you could call
+                                    myLayout->setItemLayout (barIndex, 8, 8, 8)
+        @param isBarVertical        true if it's an upright bar that you drag left and
+                                    right; false for a horizontal one that you drag up and
+                                    down
+    */
+    StretchableLayoutResizerBar (StretchableLayoutManager* layoutToUse,
+                                 int itemIndexInLayout,
+                                 bool isBarVertical);
+
+    /** Destructor. */
+    ~StretchableLayoutResizerBar();
+
+    //==============================================================================
+    /** This is called when the bar is dragged.
+
+        This method must update the positions of any components whose position is
+        determined by the StretchableLayoutManager, because they might have just
+        moved.
+
+        The default implementation calls the resized() method of this component's
+        parent component, because that's often where you're likely to apply the
+        layout, but it can be overridden for more specific needs.
+    */
+    virtual void hasBeenMoved();
+
+    //==============================================================================
+    /** This abstract base class is implemented by LookAndFeel classes. */
+    struct JUCE_API  LookAndFeelMethods
+    {
+        virtual ~LookAndFeelMethods() {}
+
+        virtual void drawStretchableLayoutResizerBar (Graphics&, int w, int h,
+                                                      bool isVerticalBar, bool isMouseOver, bool isMouseDragging) = 0;
+    };
+
+    //==============================================================================
+    /** @internal */
+    void paint (Graphics&) override;
+    /** @internal */
+    void mouseDown (const MouseEvent&) override;
+    /** @internal */
+    void mouseDrag (const MouseEvent&) override;
+
+
+private:
+    //==============================================================================
+    StretchableLayoutManager* layout;
+    int itemIndex, mouseDownPos;
+    bool isVertical;
+
+    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (StretchableLayoutResizerBar)
+};
+
+} // namespace juce