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_dsp/processors/juce_Gain.h

@@ -0,0 +1,147 @@
+/*
+  ==============================================================================
+
+   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
+{
+namespace dsp
+{
+
+/**
+    Applies a gain to audio samples as single samples or AudioBlocks.
+
+    @tags{DSP}
+*/
+template <typename FloatType>
+class Gain
+{
+public:
+    Gain() noexcept {}
+
+    //==============================================================================
+    /** Applies a new gain as a linear value. */
+    void setGainLinear (FloatType newGain) noexcept             { gain.setValue (newGain); }
+
+    /** Applies a new gain as a decibel value. */
+    void setGainDecibels (FloatType newGainDecibels) noexcept   { setGainLinear (Decibels::decibelsToGain<FloatType> (newGainDecibels)); }
+
+    /** Returns the current gain as a linear value. */
+    FloatType getGainLinear() const noexcept                    { return gain.getTargetValue(); }
+
+    /** Returns the current gain in decibels. */
+    FloatType getGainDecibels() const noexcept                  { return Decibels::gainToDecibels<FloatType> (getGainLinear()); }
+
+    /** Sets the length of the ramp used for smoothing gain changes. */
+    void setRampDurationSeconds (double newDurationSeconds) noexcept
+    {
+        if (rampDurationSeconds != newDurationSeconds)
+        {
+            rampDurationSeconds = newDurationSeconds;
+            reset();
+        }
+    }
+
+    /** Returns the ramp duration in seconds. */
+    double getRampDurationSeconds() const noexcept              { return rampDurationSeconds; }
+
+    /** Returns true if the current value is currently being interpolated. */
+    bool isSmoothing() const noexcept                           { return gain.isSmoothing(); }
+
+    //==============================================================================
+    /** Called before processing starts. */
+    void prepare (const ProcessSpec& spec) noexcept
+    {
+        sampleRate = spec.sampleRate;
+        reset();
+    }
+
+    /** Resets the internal state of the gain */
+    void reset() noexcept
+    {
+        if (sampleRate > 0)
+            gain.reset (sampleRate, rampDurationSeconds);
+    }
+
+    //==============================================================================
+    /** Returns the result of processing a single sample. */
+    template <typename SampleType>
+    SampleType JUCE_VECTOR_CALLTYPE processSample (SampleType s) noexcept
+    {
+        return s * gain.getNextValue();
+    }
+
+    /** Processes the input and output buffers supplied in the processing context. */
+    template <typename ProcessContext>
+    void process (const ProcessContext& context) noexcept
+    {
+        auto&& inBlock  = context.getInputBlock();
+        auto&& outBlock = context.getOutputBlock();
+
+        jassert (inBlock.getNumChannels() == outBlock.getNumChannels());
+        jassert (inBlock.getNumSamples() == outBlock.getNumSamples());
+
+        auto len         = inBlock.getNumSamples();
+        auto numChannels = inBlock.getNumChannels();
+
+        if (context.isBypassed)
+        {
+            gain.skip (static_cast<int> (len));
+
+            if (context.usesSeparateInputAndOutputBlocks())
+                outBlock.copy (inBlock);
+
+            return;
+        }
+
+        if (numChannels == 1)
+        {
+            auto* src = inBlock.getChannelPointer (0);
+            auto* dst = outBlock.getChannelPointer (0);
+
+            for (size_t i = 0; i < len; ++i)
+                dst[i] = src[i] * gain.getNextValue();
+        }
+        else
+        {
+            auto* gains = static_cast<FloatType*> (alloca (sizeof (FloatType) * len));
+
+            for (size_t i = 0; i < len; ++i)
+                gains[i] = gain.getNextValue();
+
+            for (size_t chan = 0; chan < numChannels; ++chan)
+                FloatVectorOperations::multiply (outBlock.getChannelPointer (chan),
+                                                 inBlock.getChannelPointer (chan),
+                                                 gains, static_cast<int> (len));
+        }
+    }
+
+private:
+    //==============================================================================
+    LinearSmoothedValue<FloatType> gain;
+    double sampleRate = 0, rampDurationSeconds = 0;
+};
+
+} // namespace dsp
+} // namespace juce