I've finally read through this string.  I appologize to David for not writing
it down when we talked.
 
What I had suggested is that __mpexl be used as the "am I on MPE?" mechanism
since the compiler predefines it.  This helps alleviate some of the makefile
changes.  Another thing that might help is to have
 
        #ifdef __mpexl
        #  define _POSIX_SOURCE
        #  define _SOCKET_SOURCE
        #endif
 
in the source where appropriate.  This would also reduce the makefile changes
required for some programs.
 
The _POSIX_SOURCE and _SOCKET_SOURCE switches are pretty much cast in cement
and are required for most ported programs.  The __mpexl vs. _MPEXL_SOURCE
discussion was something I invented since I started off using _MPEXL_SOURCE
before I discovered the __mpexl predefine.
 
I implore all of you to use __mpexl regardless of your personal feelings on
the issue of the name.  The name of this predefine has been cast in concrete
for years and there is not much benefit in discussing it or changing it.
 
The important point is that we all do it the same way.  Using __mpexl reduces
the "surprise factor" when the makefile hasn't been updated to define the
switch for the code since the compiler takes care of it for you.
 
Thanks you for your support,
 
Steve