CMP0020-------Automatically link Qt executables to qtmain target on Windows.CMake 2.8.10 and lower required users of Qt to always specify a linkdependency to the qtmain.lib static library manually on Windows.CMake 2.8.11 gained the ability to evaluate generator expressionswhile determining the link dependencies from IMPORTED targets. Thisallows CMake itself to automatically link executables which link to Qtto the qtmain.lib library when using IMPORTED Qt targets. Forapplications already linking to qtmain.lib, this should have littleimpact. For applications which supply their own alternative WinMainimplementation and for applications which use the QAxServer library,this automatic linking will need to be disabled as per thedocumentation.The OLD behavior for this policy is not to link executables to
The NEW behavior for this policy is to link executables to qtmain.libautomatically when they link to QtCore IMPORTED target.This policy was introduced in CMake version 2.8.11. CMake version|release| warns when the policy is not set and uses OLD behavior. Usethe cmake_policy command to set it to OLD or NEW explicitly.