COMPAT_SUPPORT option

["David P. Reese, Jr." <daver@xxxxxxxxxxxx>]

Now that the Linux emulator is almost completely independent of COMPAT_43,
I have to decide what to do with some pieces of code that some of the
emulators use that is buried in the source tree.  For example, we have
some COMPAT_43 code buried in ifioctl() and two of the emulators require
the COMPAT_43 syscall obreak().

I'm considering creating a COMPAT_SUPPORT flag that would compile for
example the legacy ifioctl() support which would allow emulators to be
loaded as modules.

In the case of code like obreak(), we could create some kind of a compat
library, a la NetBSD's common compat code.  This may be kind of overkill
because as it stands, obreak() is the only 43BSD syscall I would end up
throwing in the common compat code.  Over time, I could move some of
the duplicated compat code into the common subtree.  The other option
would be duplicating the body of obreak() in the two emulators that depend
on it, Linux and ibcs2.

-- 
   David P. Reese, Jr.                                     daver@xxxxxxxxxxxx
                                               http://www.gomerbud.com/daver/