missing struct vs zero length struct?

[Russ Nelson]

Now that I have Turbo C 2.0 and Turbo Debugger, I find that compiling
for source level debugging conflicts with a standard information
hiding scheme, leaving structures undefined.  :-(  Fortunately, Turbo C
doesn't complain about zero length structures.

What are the portability considerations of defining zero length structures?
Like this:

struct foo {
#ifdef INTERNAL
int bar, baz;
#endif
};

--
--russ (nelson at clutx [.bitnet | .clarkson.edu])
To surrender is to remain in the hands of barbarians for the rest of my life.
To fight is to leave my bones exposed in the desert waste.