Merge pull request #14925 from StefanBruens:handle_absolute_include_path

cmake/OpenCVGenConfig.cmake

@@ -68,7 +68,11 @@ configure_file("${OpenCV_SOURCE_DIR}/cmake/templates/OpenCVConfig-version.cmake.
 #  Part 2/3: ${BIN_DIR}/unix-install/OpenCVConfig.cmake -> For use *with* "make install"
 # -------------------------------------------------------------------------------------------
 file(RELATIVE_PATH OpenCV_INSTALL_PATH_RELATIVE_CONFIGCMAKE "${CMAKE_INSTALL_PREFIX}/${OPENCV_CONFIG_INSTALL_PATH}/" ${CMAKE_INSTALL_PREFIX})
-set(OpenCV_INCLUDE_DIRS_CONFIGCMAKE "\"\${OpenCV_INSTALL_PATH}/${OPENCV_INCLUDE_INSTALL_PATH}\" \"\${OpenCV_INSTALL_PATH}/${OPENCV_INCLUDE_INSTALL_PATH}/opencv\"")
+if (IS_ABSOLUTE ${OPENCV_INCLUDE_INSTALL_PATH})
+  set(OpenCV_INCLUDE_DIRS_CONFIGCMAKE "\"${OPENCV_INCLUDE_INSTALL_PATH}\" \"${OPENCV_INCLUDE_INSTALL_PATH}/opencv\"")
+else()
+  set(OpenCV_INCLUDE_DIRS_CONFIGCMAKE "\"\${OpenCV_INSTALL_PATH}/${OPENCV_INCLUDE_INSTALL_PATH}\" \"\${OpenCV_INSTALL_PATH}/${OPENCV_INCLUDE_INSTALL_PATH}/opencv\"")
+endif()
 
 if(USE_IPPICV)
   file(RELATIVE_PATH IPPICV_INSTALL_PATH_RELATIVE_CONFIGCMAKE "${CMAKE_INSTALL_PREFIX}" "${IPPICV_INSTALL_PATH}")