fix a bug of detect opencl

cmake/OpenCVDetectOpenCL.cmake

@@ -16,14 +16,14 @@ else()
             else()
                 set(OPENCL_LIB_SEARCH_PATH ${OPENCL_LIB_SEARCH_PATH} ${ENV_AMDSTREAMSDKROOT}/lib/x86_64)
             endif()
-        elif(ENV_CUDAPATH AND WIN32)
+        elseif(ENV_CUDAPATH AND WIN32)
             set(OPENCL_INCLUDE_SEARCH_PATH ${ENV_CUDA_PATH}/include)
             if(CMAKE_SIZEOF_VOID_P EQUAL 4)
                 set(OPENCL_LIB_SEARCH_PATH ${OPENCL_LIB_SEARCH_PATH} ${ENV_CUDA_PATH}/lib/Win32)
             else()
                 set(OPENCL_LIB_SEARCH_PATH ${OPENCL_LIB_SEARCH_PATH} ${ENV_CUDA_PATH}/lib/x64)
             endif()
-        elif(ENV_OPENCLROOT AND UNIX)
+        elseif(ENV_OPENCLROOT AND UNIX)
             set(OPENCL_INCLUDE_SEARCH_PATH ${ENV_OPENCLROOT}/inc)
             if(CMAKE_SIZEOF_VOID_P EQUAL 4)
                 set(OPENCL_LIB_SEARCH_PATH ${OPENCL_LIB_SEARCH_PATH} /usr/lib)
@@ -57,8 +57,11 @@ else()
 
         if(OPENCL_FOUND)
             set(OPENCL_LIBRARIES ${OPENCL_LIBRARY})
+			set(HAVE_OPENCL 1)
         else()
             set(OPENCL_LIBRARIES)
         endif()
+	else()
+		set(HAVE_OPENCL 1)
     endif()
 endif()