urbi-root: use libport/dlfcn.h for RTLD_HANDLE.
urbi-root: use libport/dlfcn.h for RTLD_HANDLE.

Change-Id: I343610721d63cf4f07f9c0906385fe9dbc441eeb

aldebaran/urbi,aldebaran/urbi,urbiforge/urbi,aldebaran/urbi,urbiforge/urbi,aldebaran/urbi,aldebaran/urbi,urbiforge/urbi,urbiforge/urbi,urbiforge/urbi,aldebaran/urbi,aldebaran/urbi,urbiforge/urbi,urbiforge/urbi,urbiforge/urbi,aldebaran/urbi,urbiforge/urbi