changes in external/

[Tom Tromey]

According to japi, there are a few serialization buglets in the code
in external/.

I would like to propose that we fix these and mark the fixes with a
comment along the lines of 'CLASSPATH LOCAL', so that it is clear
where we've made changes.  That way if/when we import new versions, we
will be able to see whether the change is still required.

Comments?

Tom