I'm really sorry to be taking up people's time with this, however I'm
really not familiar with Darwin at all and I'm again stuck ...

I have now installed all of the sub-packages from the XCode Developer
metapackage[1] yet ld is complaining that it can't find libXt when 
I try to make ghostscript and libXext when I try to make xv ... both
of these are present in /usr/X11R6/lib and that path appears in the
arguments for the linker in both cases ... 

[1] which includes:

    Developer Tools Software
    gcc 3.3
    gcc 3.1
    Mac OS X SDK
    Developer Documentation
    Developer Example Software
    BSD SDK
    Cross-Development
      Mac OS X 10.1 SDK
      Mac OS X 10.2.8 SDK
      Mac OS X 10.3 SDK
    X11 SDK
    Java App. Servers Development
    Dec 2003 Developer Tools Extras
    CHUD Tools

-- 
Malcolm Herbert                                    System Administrator
ph [990] 54881 rm 28-241                          School of GeoSciences