moving HAL-related CMakeLists.txt to 'hal' sub-dir

3rdparty/openvx/CMakeLists.txt

-add_library(openvx_hal STATIC hal/openvx_hal.cpp hal/openvx_hal.hpp include/ivx.hpp include/ivx_lib_debug.hpp)
-target_include_directories(openvx_hal PUBLIC
-  ${CMAKE_CURRENT_SOURCE_DIR}/hal
-  ${CMAKE_CURRENT_SOURCE_DIR}/include
-  ${CMAKE_SOURCE_DIR}/modules/core/include
-  ${CMAKE_SOURCE_DIR}/modules/imgproc/include
-  ${OPENVX_INCLUDE_DIR})
-target_link_libraries(openvx_hal LINK_PUBLIC ${OPENVX_LIBRARIES})
-set_target_properties(openvx_hal PROPERTIES POSITION_INDEPENDENT_CODE TRUE)
-set_target_properties(openvx_hal PROPERTIES ARCHIVE_OUTPUT_DIRECTORY ${3P_LIBRARY_OUTPUT_PATH})
-if(NOT BUILD_SHARED_LIBS)
-  ocv_install_target(openvx_hal EXPORT OpenCVModules ARCHIVE DESTINATION ${OPENCV_3P_LIB_INSTALL_PATH} COMPONENT dev)
+if(NOT HAVE_OPENVX)
+  message(STATUS "OpenVX is not available, disabling openvx-related HAL and stuff")
+  return()
 endif()
 
-set(OPENVX_HAL_FOUND TRUE PARENT_SCOPE)
-set(OPENVX_HAL_VERSION 0.0.1 PARENT_SCOPE)
-set(OPENVX_HAL_LIBRARIES "openvx_hal" PARENT_SCOPE)
+set(OPENCV_3P_OPENVX_DIR ${CMAKE_CURRENT_SOURCE_DIR})
+add_subdirectory(hal)
\ No newline at end of file
-set(OPENVX_HAL_HEADERS "${CMAKE_CURRENT_SOURCE_DIR}/hal/openvx_hal.hpp" PARENT_SCOPE)
-set(OPENVX_HAL_INCLUDE_DIRS "${CMAKE_CURRENT_SOURCE_DIR}/hal" "${OPENVX_INCLUDE_DIR}" PARENT_SCOPE)

3rdparty/openvx/hal/CMakeLists.txt

+add_library(openvx_hal STATIC openvx_hal.cpp openvx_hal.hpp ${OPENCV_3P_OPENVX_DIR}/include/ivx.hpp ${OPENCV_3P_OPENVX_DIR}/include/ivx_lib_debug.hpp)
+target_include_directories(openvx_hal PUBLIC
+  ${CMAKE_CURRENT_SOURCE_DIR}
+  ${OPENCV_3P_OPENVX_DIR}/include
+  ${CMAKE_SOURCE_DIR}/modules/core/include
+  ${CMAKE_SOURCE_DIR}/modules/imgproc/include
+  ${OPENVX_INCLUDE_DIR})
+target_link_libraries(openvx_hal LINK_PUBLIC ${OPENVX_LIBRARIES})
+set_target_properties(openvx_hal PROPERTIES POSITION_INDEPENDENT_CODE TRUE)
+set_target_properties(openvx_hal PROPERTIES ARCHIVE_OUTPUT_DIRECTORY ${3P_LIBRARY_OUTPUT_PATH})
+if(NOT BUILD_SHARED_LIBS)
+  ocv_install_target(openvx_hal EXPORT OpenCVModules ARCHIVE DESTINATION ${OPENCV_3P_LIB_INSTALL_PATH} COMPONENT dev)
+endif()
+
+set(OPENVX_HAL_FOUND TRUE CACHE INTERNAL "")
+set(OPENVX_HAL_VERSION 0.0.1 CACHE INTERNAL "")
+set(OPENVX_HAL_LIBRARIES "openvx_hal" CACHE INTERNAL "")
+set(OPENVX_HAL_HEADERS "${CMAKE_CURRENT_SOURCE_DIR}/openvx_hal.hpp" CACHE INTERNAL "")
+set(OPENVX_HAL_INCLUDE_DIRS "${CMAKE_CURRENT_SOURCE_DIR}" "${OPENCV_3P_OPENVX_DIR}/include" "${OPENVX_INCLUDE_DIR}" CACHE INTERNAL "")