ENH: Improve OTBConfig.cmake.in and UseOTB.cmake.in files for setting externals libraries dir

OTBConfig.cmake.in

@@ -13,6 +13,9 @@
 # Option use external ITK.
 SET(OTB_USE_EXTERNAL_ITK "@OTB_USE_EXTERNAL_ITK@")
 
+# Option use external ITK.
+SET(OTB_USE_EXTERNAL_FLTK "@OTB_USE_EXTERNAL_FLTK@")
+
 
 # The OTB source tree.
 SET(OTB_SOURCE_DIR "@OTB_SOURCE_DIR@")
@@ -76,6 +79,7 @@ SET(OTB_VXL_DIR "@OTB_VXL_DIR@")
 
 SET(OTB_FLTK_FLUID_EXECUTABLE "@FLTK_FLUID_EXECUTABLE@")
 SET(OTB_ITK_DIR "@ITK_DIR@")
+SET(OTB_FLTK_DIR "@FLTK_DIR@")
 
 # FLTK informations
 SET(FLTK_FLUID_EXECUTABLE "@OTB_FLTK_FLUID_EXECUTABLE@")

UseOTB.cmake.in

@@ -67,9 +67,15 @@ IF(OTB_USE_SYSTEM_VXL)
   ENDIF(VXL_FOUND)
 ENDIF(OTB_USE_SYSTEM_VXL)
 
-IF(OTB_USE_EXTERNAL_FLTK)
-  SET(FLTK_FLUID_EXECUTABLE ${OTB_FLTK_FLUID_EXECUTABLE})
-ENDIF(OTB_USE_EXTERNAL_FLTK)
+#WHERE TO FIND FLTK
+IF(OTB_USE_VISU_GUI)
+  IF(OTB_USE_EXTERNAL_FLTK)
+    SET(FLTK_FLUID_EXECUTABLE ${OTB_FLTK_FLUID_EXECUTABLE})
+    INCLUDE(${OTB_FLTK_DIR}/FLTKConfig.cmake)
+    LINK_DIRECTORIES(${FLTK_LIBRARY_DIRS})
+  ENDIF(OTB_USE_EXTERNAL_FLTK)
+ENDIF(OTB_USE_VISU_GUI)
+
 
 #WHERE TO FIND ITK
 IF(OTB_USE_EXTERNAL_ITK)