Update React Native from 0.59.10 to 0.61.5: XCode Build Error with .cpp files using OpenCV

I'm in the process of porting a React Native (0.59.10) to React Native 0.61.5, and am having troubles getting my custom OpenCV module (written in C++) to work. I'm getting multiple build errors in XCode (11.3.1) on Mac OSX Mojave (10.14.6 (18G103)), my guess is that the C++ environment in XCode is not set up properly, but then again I'm no expert on that and the error messages don't give me a good starting point to investigate.

I attached a screenshot of XCode's output ...

..and the highlighted line #29 of the mentioned .pch file:

The first error message is:

/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/ctime:58:9: No member named 'clock_t' in the global namespace

Thanks!