The RAM memory area symbols are referred by the startup code. The 64k and 128k variant say "for assembler" so it may be not necessary to do that there. However given the "limited" state of documentation for the target I don't assign too much value to those statements.
Additionally it's unclear to me why two variants provide symbols for the ROM memory.
In normal situations it isn't too useful to define symbols for optional segments as those symbols can't be presumed to be always present.
I in fact suspect that most currently present combinations of 'define' and 'optional' aren't useful - apart form the overlay configurations of course.
The way we want to use the INITBSS segment - and especially the fact that it won't have the type bss on all ROM based targets - means that the name INITBSS is misleading. After all INIT is the best name from my perspective as it serves several purposes and therefore needs a rather generic name.
Unfortunately this means that the current INIT segment needs to be renamed too. Looking for a short (ideally 4 letter) name I came up with ONCE as it contains all code (and data) accessed only once during initialization.
