Building 5.15 with Xcode-12 beta

[glennr]

Is it possible yet to build Qt 5.15 using Xcode 12 beta on MacOS?

With the latest from the 5.15 branch I'm seeing errors like this:

../../3rdparty/chromium/components/viz/common/gpu/metal_api_proxy.mm:595:1: error: cannot initialize a parameter of type 'MTLTimestamp * _Nonnull' (aka 'unsigned long long *') with an lvalue of type 'NSUInteger * _Nonnull' (aka 'unsigned long *')
PROXY_METHOD2(void, sampleTimestamps, NSUInteger*, gpuTimestamp, NSUInteger*)

Is there a patch for this?