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/lookandfeel/juce_LookAndFeel_V3.h

@@ -0,0 +1,99 @@
+/*
+  ==============================================================================
+
+   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
+{
+
+//==============================================================================
+/**
+    The latest JUCE look-and-feel style, as introduced in 2013.
+    @see LookAndFeel, LookAndFeel_V1, LookAndFeel_V2
+
+    @tags{GUI}
+*/
+class JUCE_API  LookAndFeel_V3   : public LookAndFeel_V2
+{
+public:
+    LookAndFeel_V3();
+    ~LookAndFeel_V3();
+
+    //==============================================================================
+    void drawButtonBackground (Graphics&, Button&, const Colour& backgroundColour,
+                               bool isMouseOverButton, bool isButtonDown) override;
+
+    void drawTableHeaderBackground (Graphics&, TableHeaderComponent&) override;
+
+    void drawTreeviewPlusMinusBox (Graphics&, const Rectangle<float>& area,
+                                   Colour backgroundColour, bool isOpen, bool isMouseOver) override;
+    bool areLinesDrawnForTreeView (TreeView&) override;
+    int getTreeViewIndentSize (TreeView&) override;
+
+    Button* createDocumentWindowButton (int buttonType) override;
+
+    void drawComboBox (Graphics&, int width, int height, bool isButtonDown,
+                       int buttonX, int buttonY, int buttonW, int buttonH, ComboBox& box) override;
+
+    void drawKeymapChangeButton (Graphics&, int width, int height, Button& button, const String& keyDescription) override;
+
+    void drawPopupMenuBackground (Graphics&, int width, int height) override;
+    void drawMenuBarBackground (Graphics&, int width, int height, bool, MenuBarComponent&) override;
+
+    int getTabButtonOverlap (int tabDepth) override;
+    int getTabButtonSpaceAroundImage() override;
+    void drawTabButton (TabBarButton&, Graphics&, bool isMouseOver, bool isMouseDown) override;
+    void drawTabAreaBehindFrontButton (TabbedButtonBar& bar, Graphics& g, int w, int h) override;
+
+    void drawTextEditorOutline (Graphics&, int width, int height, TextEditor&) override;
+
+    void drawStretchableLayoutResizerBar (Graphics&, int w, int h, bool isVerticalBar, bool isMouseOver, bool isMouseDragging) override;
+
+    bool areScrollbarButtonsVisible() override;
+
+    void drawScrollbar (Graphics&, ScrollBar&, int x, int y, int width, int height, bool isScrollbarVertical,
+                        int thumbStartPosition, int thumbSize, bool isMouseOver, bool isMouseDown) override;
+
+    void drawLinearSlider (Graphics&, int x, int y, int width, int height,
+                           float sliderPos, float minSliderPos, float maxSliderPos,
+                           const Slider::SliderStyle, Slider&) override;
+
+    void drawLinearSliderBackground (Graphics&, int x, int y, int width, int height,
+                                     float sliderPos, float minSliderPos, float maxSliderPos,
+                                     const Slider::SliderStyle, Slider&) override;
+
+    void drawConcertinaPanelHeader (Graphics&, const Rectangle<int>& area, bool isMouseOver, bool isMouseDown,
+                                    ConcertinaPanel&, Component&) override;
+
+    Path getTickShape (float height) override;
+    Path getCrossShape (float height) override;
+
+    static void createTabTextLayout (const TabBarButton& button, float length, float depth, Colour colour, TextLayout&);
+
+private:
+    Image backgroundTexture;
+    Colour backgroundTextureBaseColour;
+};
+
+} // namespace juce