setting the policy to new is not needed, because we demand cmake_mini…

…mum_required(VERSION 3.8) and this policy was introduced in cmake 3.3, see heere : https://cmake.org/cmake/help/latest/policy/CMP0057.html

this means any newer cmake is using the new policy (unless somebody would set it to old explicitly)

cmake/config.cmake

@@ -38,8 +38,6 @@ check_function_exists("poll" PQXX_HAVE_POLL)
 
 set(CMAKE_REQUIRED_LIBRARIES pq)
 
-cmake_policy(SET CMP0057 NEW)
-
 # check_cxx_source_compiles requires CMAKE_REQUIRED_DEFINITIONS to specify
 # compiling arguments. Workaround: Push CMAKE_REQUIRED_DEFINITIONS
 if(CMAKE_REQUIRED_DEFINITIONS)