The option mentioned in the man page sections on manipulating RPATH actually work on RUNPATH. Please disregard this bug if this is common notation, but I would expect the man page to say "Change the RUNPATH of the executable ..."
.IP "--set-rpath RPATH"
Change the RPATH of the executable or library to RPATH.
I only found out that --set-rpath sets DT_RUNPATH instead of RPATH after reading through the --force-rpath section.