ld returns uncleanly

[utzoo!henry]

The V7 ld has a nonzero exit status when undefined external symbols
exist in its final output, even when the options fed to it clearly
indicate that this is legitimate.  This screws up several things,
including use with make.  Does anybody know if this "feature" really
is of any use?  (Note that you can test for undefined externals using
nm and grep, so this obvious use is unimportant.)  I would like to
eliminate it by putting the exit-status "|= 01" inside the same set of
if's that govern the undefined-symbols error messages.  Comments?