SysV.3 to SysV.4 binary compatibility.

[Jay Logue]

While I don't know the precise extent of binary compatibility between
SVR3 and R4, I have taken executables from an SCO 3.2.2 box and run
them on an AT&T version of R4 for the 386, without any problems.  The
executables are Emacs 18.55 and GDB 3.6, both compiled with GCC.
Emacs has been running flawlessly, however GDB is completely useless
because of the new executable format used by R4 (ELF).  I was able to
get GDB to debug itself (including setting breakpoints and stopping at
those breakpoints), so it does appear to work.  Hopefully someone will
develop ELF patches for the GNU development set soon and this will no
longer be a problem.

I'd say if you have an executable you wish to transfer, give it a
try.  I occurs to me that this level of compatibility should cover
a lot of applications.

Jay.