\loadmapfile[texnansi-adobe-sabon.map]

\starttypescript [serif] [sabon] [texnansi]
  \definefontsynonym [Sabon-Roman][texnansi-sar][encoding=texnansi]
\stoptypescript

\starttypescript [serif] [sabon] [name]
  \definefontsynonym [Serif][Sabon-Roman]
\stoptypescript

\starttypescript [Sabon] 
  \definetypeface [Sabon][rm][serif][sabon][default][encoding=texnansi]
\stoptypescript

\startfonthandling [sabon]
%
% Comment out the next line and the job runs ok. 
%
  \defineprotrudefactor ?  0  .05
\stopfonthandling


