dtksh: use bin/package flat make instead of shell

Shell isn't portable, so upstream ksh93 has a "flat" function that we can use
to put binaries in a static place that doesn't require a shell command. We still
do need an intermediate setup.sh shell script due to a bug in ksh that object
files aren't being put in lib, and FEATURE not in include. We also cut out some
 unused symbols, and a hpux specific implementation of dynlib (new hpux should
 conform to the posix implementation anyhow.)

cde/programs/dtksh/README-DEVELOPER

@@ -2,10 +2,9 @@
 
 (NOTE: As of CDE 2.3.1 and later, this entire document is obsolete and only kept
  for historical purposes, the updating process has been streamlined to a simple
- three step process:
+ two step process:
  1. cd ksh93; git pull
  2. Merge upstream init.c with ours, keeping all of our changes.
- 3. Merge upstream builtins.c. doing the same as init.c
  and thats all there is to it.)
 
 IMPORTANT!!!  PLEASE READ ON!!