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_box2d/box2d/Dynamics/b2TimeStep.h

@@ -0,0 +1,70 @@
+/*
+* Copyright (c) 2006-2011 Erin Catto http://www.box2d.org
+*
+* This software is provided 'as-is', without any express or implied
+* warranty.  In no event will the authors be held liable for any damages
+* arising from the use of this software.
+* Permission is granted to anyone to use this software for any purpose,
+* including commercial applications, and to alter it and redistribute it
+* freely, subject to the following restrictions:
+* 1. The origin of this software must not be misrepresented; you must not
+* claim that you wrote the original software. If you use this software
+* in a product, an acknowledgment in the product documentation would be
+* appreciated but is not required.
+* 2. Altered source versions must be plainly marked as such, and must not be
+* misrepresented as being the original software.
+* 3. This notice may not be removed or altered from any source distribution.
+*/
+
+#ifndef B2_TIME_STEP_H
+#define B2_TIME_STEP_H
+
+#include "../Common/b2Math.h"
+
+/// Profiling data. Times are in milliseconds.
+struct b2Profile
+{
+	float32 step;
+	float32 collide;
+	float32 solve;
+	float32 solveInit;
+	float32 solveVelocity;
+	float32 solvePosition;
+	float32 broadphase;
+	float32 solveTOI;
+};
+
+/// This is an internal structure.
+struct b2TimeStep
+{
+	float32 dt;			// time step
+	float32 inv_dt;		// inverse time step (0 if dt == 0).
+	float32 dtRatio;	// dt * inv_dt0
+	juce::int32 velocityIterations;
+	juce::int32 positionIterations;
+	bool warmStarting;
+};
+
+/// This is an internal structure.
+struct b2Position
+{
+	b2Vec2 c;
+	float32 a;
+};
+
+/// This is an internal structure.
+struct b2Velocity
+{
+	b2Vec2 v;
+	float32 w;
+};
+
+/// Solver Data
+struct b2SolverData
+{
+	b2TimeStep step;
+	b2Position* positions;
+	b2Velocity* velocities;
+};
+
+#endif