COMP: fix #531 : internal FLTK defines only FLTK_INCLUDE_DIRS, while FindFLTK defines FLTK_INCLUDE_DIR
COMP: fix #531 : internal FLTK defines only FLTK_INCLUDE_DIRS, while FindFLTK defines FLTK_INCLUDE_DIR

orfeotoolbox/OTB,orfeotoolbox/OTB,orfeotoolbox/OTB,orfeotoolbox/OTB,orfeotoolbox/OTB,orfeotoolbox/OTB