Modify slight the CMake so that it compiles with CGAL 6.0 ❤️

now compiles on 5.6 + 6.0 and all unit tests pass

CMakeLists.txt

@@ -7,7 +7,7 @@ cmake_minimum_required (VERSION 3.16)
 project( val3dity )
 
 
-add_definitions(-std=c++14)
+add_definitions(-std=c++17)
 
 set( CMAKE_BUILD_TYPE "Release")
 set( CMAKE_CXX_FLAGS "-O2" )
@@ -25,7 +25,6 @@ endif(MSVC)
 # CGAL
 find_package( CGAL QUIET COMPONENTS )
 if ( CGAL_FOUND )
-  include( ${CGAL_USE_FILE} )
   message(STATUS "CGAL found")
   message(STATUS ${CGAL_LIBRARIES})
   message(STATUS ${CGAL_3RD_PARTY_LIBRARIES})