lorder —
list dependencies for object files
The lorder utility uses
  nm(1) to determine interdependencies
  in the list of object files specified on the command line.
  lorder outputs a list of file names where the first
  file contains a symbol which is defined by the second file.
The output is normally used with
    tsort(1) when a library is
    created to determine the optimum ordering of the object modules so that all
    references may be resolved in a single pass of the loader.
ar cr library.a `lorder ${OBJS} | tsort`
 
An lorder utility appeared in
  Version 7 AT&T UNIX.