Cmake build: Adapt to compile with qt5.11

Cmake build: Adapt to compile with qt5.11

Since qt5_use_modules() is removed from QT5 (as spotted
by Jürgen Spitzmüller), we had to create own version
of this macro.

According to this page:
http://doc.qt.io/qt-5/cmake-manual.html
the way to replace use of qt5_use_modules() for module "_mod" and target "_target"
is to use
  1.) cmake_minimum_required(VERSION 3.1.0)
  2.) find_package(Qt5${_mod} CONFIG REQUIRED)
  3.) target_link_libraries(${_target} Qt5::${_mod})
The last one sets all reguired libraries, compile flags and needed includes for the ${_target}

Disable possible warn about not known policy

Extend Clang compiler detection to cover Apple CLang

(cherry picked from commit d6b21e20e254c96d963c6ab4988ad635f8f4e44b)
(cherry picked from commit 72a2f922393f8029b658fffe3c5a2e3e2c81ac1d)
(cherry picked from commit 6343452a7397a5ac4b84af30d61c4d7fca5afbc1)
(cherry picked from commit cb08d4a879bf63222a4462308b614d3209607737)
(cherry picked from commit 1bf4d7b0fc2bc4c700e7cecc1e6e3c7faf4f03a5)