Using Xcode 7 there's a missing-override compiler warning in juce_VST3_Wrapper.cpp
This commit suppresses the warning for that line: https://github.com/soundradix/JUCE/commit/fd7a243ea61069ab7b42ca5fb1662b5ef21d5e8d
An alternative fix could be to not use the SDK's macro and write that code with the override keyword (the macro expands to just two lines).
btw the warning comes up with both VST SDK 3.6.5 (latest) and VST SDK 3.6.0
Cheers, Yair