BUG #5631: psql dumps core during command editing

The following bug has been logged online:

Bug reference: 5631
Logged by: David Kensiski
Email address: David(at)Schoolloop(dot)com
PostgreSQL version: 8.4
Operating system: Solaris 10
Description: psql dumps core during command editing
Details:

The psql binary (64-bit from binary install) dumps core when I attempt to
edit the input line after a few characters are entered:

tombu(at)i2:~$ psql homerdb
psql (8.4.4)
Type "help" for help.

homerdb=# abcde(Ctrl-A)Segmentation Fault (core dumped)

Note that "abcd(Ctrl-A)" doesn't result in a Seg Fault, though
"abcde(Ctrl-A)" does.

Here's the tail end of a truss of the psql process:

read(0, " d", 1) = 1
write(1, " d", 1) = 1
read(0, " e", 1) = 1
write(1, " e", 1) = 1
read(0, "01", 1) = 1
Incurred fault #6, FLTBOUNDS %pc = 0xFFFFFD7FFEF087C2
siginfo: SIGSEGV SEGV_MAPERR addr=0xFFFFFFFFFEF2D500
Received signal #11, SIGSEGV [default]
siginfo: SIGSEGV SEGV_MAPERR addr=0xFFFFFFFFFEF2D500

Alas, I'd give you a backtrace, but I'm running the 64-bit binary and only
have a 32-bit gdb.