These nroff device description tables are used in AT&T DOCUMENT
PREPARATION 3.51.  They should be inserted in
directory /usr/lib/nterm.  Maintain the relative links between the
tab.470*, tab.475*, and tab.8510*files; between the tab.478*,
tab.479*, and tab.ibm* files.  
Set permission to 444 for all files.
The makefile doesn't quite work.
