The packfile contains for string constants the STRING internal field
"flags". This is used for various *internal* purposes, e.g. defining
that a string is external or COWed.
So a badly (i.e. non NULL) set flags field could seriously damage
parrots operation WRT strings.
IMHO, this field doesn't belong into the PBC. In the meantime, I would
clear flags near packfile.c:930.
leo
