Don't gratuitously pipe thru a cat(1) if NODOCCOMPRESS.
Only create _stamp.extra when necessary.
Get rid of SOELIMPP and OBJS.
Use Groff version of soelim(1); we need its -I option
for the following to work.
Don't needlessly chdir to SRCDIR. Only a few documents
need CD_HACK, and those that need it either use refer(1)
or .PSPIC macro which internally uses the .psbb call.
This does not use the standard build macros for two reasons:
1. There's more than one document (paper and appendix).
2. The standard build macros need revision anyway (we shouldn't need
to set variables to get PostScript output, it should be a separate
target).
If anybody feels offended by this breach of style, feel free to fix
it.
