Cleaned up "iff" statement.
Cleaned up "iff" statement.

In Trylon 1, a symbol was considered defined if it was defined in the
build-settings, *or* if it was defined in the context.  The latter case has
been removed; only the build-settings count.

stevefolta/trylon,stevefolta/trylon,stevefolta/trylon,stevefolta/trylon,stevefolta/trylon