save history error, ignorable?

I just upgraded from postgres 7.x.x to 8.1.0 and am getting the
following error from cmd-line psql:

could not save history to file "<my_home_dir>/.psql_history":
Invalid argument

Searching the archives, I found a thread about this error wherein the
poster "solved" the problem by commenting out the reporting code in
the source file. Tom's reply (*) suggests a discrepancy in libraries
on MacOSX. Nonetheless, I *seem* to have the intended functionality
(readline history on the cmd-line), in spite of the error msg.

Questions:

- Is the error msg ignorable?

- Else, is there a post-compile fix for the problem?

- Does the correct lib exist on MacOSX? If so, is there doco on how
to specify its use on compiling?

My platform:

MacOSX v10.4.2
PostgreSQL v8.1.0

Thanks in advance!
Scott

(*) [ from Tom Lane, via archives search ]
The Postgres code in that area hasn't changed at all. Maybe in this
build you linked against Apple's builtin libedit instead of libreadline?
libedit seems to have a bizarre definition of the result value from
write_history()