You may be linking X libraries, which have complex interdependencies,
  in the wrong order. Mark Kilgard <mjk@hoot.asd.sgi.com> provided this
  handy chart:

  libXm--libXirisw
                  \
                   libXt--libXmu--libgl--libXi--libXext--libX11
                  /
            libXaw

  Libraries should be listed in the same order on the cc or ld command
  line, left to right, as they appear above. If you don't use routines
  from a library, of course, you don't need it.

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