Merge pull request #10223 from vpisarev:ocl_mac_fixes

* fixed OpenCL functions on Mac, so that the tests pass

* fixed compile warnings; temporarily disabled OCL branch of TV L1 optical flow on mac

* fixed other few warnings on macos

modules/video/src/tvl1flow.cpp

@@ -392,9 +392,11 @@ void OpticalFlowDual_TVL1::calc(InputArray _I0, InputArray _I1, InputOutputArray
 {
     CV_INSTRUMENT_REGION()
 
+#ifndef __APPLE__
     CV_OCL_RUN(_flow.isUMat() &&
                ocl::Image2D::isFormatSupported(CV_32F, 1, false),
                calc_ocl(_I0, _I1, _flow))
+#endif
 
     Mat I0 = _I0.getMat();
     Mat I1 = _I1.getMat();