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_audio_basics/effects/juce_Decibels.h

@@ -0,0 +1,112 @@
+/*
+  ==============================================================================
+
+   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.
+
+   The code included in this file is provided under the terms of the ISC license
+   http://www.isc.org/downloads/software-support-policy/isc-license. Permission
+   To use, copy, modify, and/or distribute this software for any purpose with or
+   without fee is hereby granted provided that the above copyright notice and
+   this permission notice appear in all copies.
+
+   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
+{
+
+//==============================================================================
+/**
+    This class contains some helpful static methods for dealing with decibel values.
+
+    @tags{Audio}
+*/
+class Decibels
+{
+public:
+    //==============================================================================
+    /** Converts a dBFS value to its equivalent gain level.
+
+        A gain of 1.0 = 0 dB, and lower gains map onto negative decibel values. Any
+        decibel value lower than minusInfinityDb will return a gain of 0.
+    */
+    template <typename Type>
+    static Type decibelsToGain (Type decibels,
+                                Type minusInfinityDb = Type (defaultMinusInfinitydB))
+    {
+        return decibels > minusInfinityDb ? std::pow (Type (10.0), decibels * Type (0.05))
+                                          : Type();
+    }
+
+    /** Converts a gain level into a dBFS value.
+
+        A gain of 1.0 = 0 dB, and lower gains map onto negative decibel values.
+        If the gain is 0 (or negative), then the method will return the value
+        provided as minusInfinityDb.
+    */
+    template <typename Type>
+    static Type gainToDecibels (Type gain,
+                                Type minusInfinityDb = Type (defaultMinusInfinitydB))
+    {
+        return gain > Type() ? jmax (minusInfinityDb, static_cast<Type> (std::log10 (gain)) * Type (20.0))
+                             : minusInfinityDb;
+    }
+
+    //==============================================================================
+    /** Converts a decibel reading to a string.
+
+        By default the returned string will have the 'dB' suffix added, but this can be removed by
+        setting the shouldIncludeSuffix argument to false. If a customMinusInfinityString argument
+        is provided this will be returned if the value is lower than minusInfinityDb, otherwise
+        the return value will be "-INF".
+    */
+    template <typename Type>
+    static String toString (Type decibels,
+                            int decimalPlaces = 2,
+                            Type minusInfinityDb = Type (defaultMinusInfinitydB),
+                            bool shouldIncludeSuffix = true,
+                            StringRef customMinusInfinityString = {})
+    {
+        String s;
+        s.preallocateBytes (20);
+
+        if (decibels <= minusInfinityDb)
+        {
+            if (customMinusInfinityString.isEmpty())
+                s << "-INF";
+            else
+                s << customMinusInfinityString;
+        }
+        else
+        {
+            if (decibels >= Type())
+                s << '+';
+
+            if (decimalPlaces <= 0)
+                s << roundToInt (decibels);
+            else
+                s << String (decibels, decimalPlaces);
+        }
+
+        if (shouldIncludeSuffix)
+            s << " dB";
+
+        return s;
+    }
+
+private:
+    //==============================================================================
+    enum { defaultMinusInfinitydB = -100 };
+
+    Decibels() = delete; // This class can't be instantiated, it's just a holder for static methods..
+};
+
+} // namespace juce