COMP: Applying path to fix compilation error with gcc4.4 (invalid conversion from ‘int (*)(const void*, const void*)’ to ‘int (*)(const dirent**, const dirent**))

BUG: OTB_USE_EXTERNAL_FLTK option will not appear, even if FLTK is not found on the system. It seems that CMAKE_DEPENDENT_OPTION is not behaving like expected.