Lattice/UNIX incompatibility

[Doug Gwyn <gwyn>]

> To get the unix multiple declaration effect, you need only make the
> declarations look like labelled COMMON to the linker.  This reserves space,
> with all the areas overlapping and the *largest* determining the amount of
> space allocated by the linker.

Many such linkers impose unacceptable restrictions on labeled COMMON, such
as: only a small number of them allowed; aligned on 4Kb boundaries; etc.

Although Ritchie favors the COMMON model, due to lack of universality the
ANSI C standards committee has settled on the DEF/REF model, with the COMMON
model relegated to the "Common extensions" appendix.