Merge remote-tracking branch 'upstream/3.4' into merge-3.4

cmake/OpenCVDetectPython.cmake

@@ -177,7 +177,7 @@ if(NOT ${found})
 
     if(NOT ANDROID AND NOT IOS)
       if(CMAKE_HOST_UNIX)
-        execute_process(COMMAND ${_executable} -c "from distutils.sysconfig import *; print(get_python_lib())"
+        execute_process(COMMAND ${_executable} -c "from sysconfig import *; print(get_path('purelib'))"
                         RESULT_VARIABLE _cvpy_process
                         OUTPUT_VARIABLE _std_packages_path
                         OUTPUT_STRIP_TRAILING_WHITESPACE)

cmake/OpenCVFindLibsGUI.cmake

@@ -66,7 +66,6 @@ if(WITH_OPENGL)
     find_package (OpenGL QUIET)
     if(OPENGL_FOUND)
       set(HAVE_OPENGL TRUE)
-      list(APPEND OPENCV_LINKER_LIBS ${OPENGL_LIBRARIES})
       if(QT_QTOPENGL_FOUND)
         set(HAVE_QT_OPENGL TRUE)
       else()