COMP: add hint about OpenCV location for MacPort

CMake/ImportOpenCV.cmake

@@ -5,7 +5,11 @@ MARK_AS_ADVANCED(OTB_USE_OPENCV)
 
 IF(OTB_USE_OPENCV)
   MESSAGE(STATUS "  Enabling OpenCV support")
-  FIND_PACKAGE(OpenCV REQUIRED)
+  FIND_PACKAGE(OpenCV
+               REQUIRED
+               PATHS
+                 /opt/local/lib/cmake # MacPort
+               )
   MESSAGE(STATUS "  Found OpenCV ${OpenCV_VERSION_MAJOR}.${OpenCV_VERSION_MINOR}.${OpenCV_VERSION_PATCH}")
   MESSAGE(STATUS "  OpenCV include directory: ${OpenCV_INCLUDE_DIRS}")
 ELSE()

CMake/UseOTB.cmake.in

@@ -161,7 +161,12 @@ IF(OTB_USE_EXTERNAL_TINYXML)
 ENDIF(OTB_USE_EXTERNAL_TINYXML)
 
 IF(OTB_USE_OPENCV)
-  FIND_PACKAGE(OpenCV REQUIRED)
+  FIND_PACKAGE(OpenCV
+               REQUIRED
+               PATHS
+                /opt/local/lib/cmake # MacPort
+               )
+
   INCLUDE_DIRECTORIES(${OpenCV_INCLUDE_DIRS})
 ENDIF()