message: remove old CMake policy settings that are no longer needed
diff: @@ -18,22 +18,6 @@ set(CMAKE_DISABLE_SOURCE_CHANGES ON)
  set(CMAKE_DISABLE_IN_SOURCE_BUILD ON)
  cmake_minimum_required(VERSION 3.1)
  -cmake_policy(SET CMP0003 NEW) # since 2.6
  -if(POLICY CMP0015)
  - cmake_policy(SET CMP0015 NEW) # since 2.8.1
  -endif()
  -if(POLICY CMP0020)
  - cmake_policy(SET CMP0020 NEW) # since 2.8.11
  -endif()
  -if(POLICY CMP0042)
  - cmake_policy(SET CMP0042 NEW) # since 3.0
  -endif()
  -if(POLICY CMP0048)
  - cmake_policy(SET CMP0048 OLD) # since 3.0
  -endif()
  -if(POLICY CMP0054)
  - cmake_policy(SET CMP0054 OLD) # since 3.1
  -endif()
  if(POLICY CMP0074)
  cmake_policy(SET CMP0074 NEW) # since 3.12
  endif()
  