Local symbols like 32768$ (and such long ones can be generated
automatically by macros) are suffixed with the "local symbol block number"
to make different labels in different local symbol blocks:
32768$12345.
However, this becomes longer than the regular symbol length (6).
So, to avoid changing these labels, they are not truncated at this length.
The listing code is updated to deal with the longest symbol name lengt
it encounters in the symbol table.