Fix bug 1615. This removes the fixed-size buffer in parse_reclbl.

Fix bug 1615. This removes the fixed-size buffer in parse_reclbl.
(You just can't trust users.)
The big buffer used for everything else is used for port names as
well. The port name is strduped and stored via tmpport until the
field is fully parsed. It is then attached to the field.

Also, in case of errors, the code now cleans up the partially constructed
field structure. Previously, this just became lost memory.