[ue4][cpp] UE4 pulls in various system headers on macOS that collide with our types. Fixes #1150.

spine-cpp/spine-cpp/src/spine/AnimationState.cpp

@@ -44,7 +44,7 @@
 
 using namespace Spine;
 
-void dummyOnAnimationEventFunc(AnimationState *state, EventType type, TrackEntry *entry, Event *event = NULL) {
+void dummyOnAnimationEventFunc(AnimationState *state, spine::EventType type, TrackEntry *entry, Event *event = NULL) {
 	SP_UNUSED(state);
 	SP_UNUSED(type);
 	SP_UNUSED(entry);

spine-cpp/spine-cpp/src/spine/SkeletonBounds.cpp

@@ -195,7 +195,7 @@ bool SkeletonBounds::intersectsSegment(Polygon *polygon, float x1, float y1, flo
 	return false;
 }
 
-Polygon *SkeletonBounds::getPolygon(BoundingBoxAttachment *attachment) {
+spine::Polygon *SkeletonBounds::getPolygon(BoundingBoxAttachment *attachment) {
 	int index = _boundingBoxes.indexOf(attachment);
 
 	return index == -1 ? NULL : _polygons[index];