CMake Warning \(dev\) in CMakeLists\.txt:
  Policy CMP0209 is not set: Verify interface header sets checks executables
  without exports\.  Run "cmake --help-policy CMP0209" for policy details\.
  Use the cmake_policy command to set the policy and suppress this warning\.

  Executable target "exe" has interface header file sets, but it does not
  enable exports\.  Those headers would be verified under CMP0209 NEW
  behavior\.

This warning is for project developers\.  Use -Wno-dev to suppress it\.
