message: Require CMake version 3.15 (3.12 on Windows)
diff: -cmake_minimum_required(VERSION 3.4)
  +if(WIN32)
  + cmake_minimum_required(VERSION 3.12)
  +else()
  + cmake_minimum_required(VERSION 3.15)
  +endif()
  set(CMAKE_BUILD_TYPE Debug CACHE STRING "")
  project(RealmCore)
  