diff -p can truncate in the middle of a multi-byte character

To reproduce, try this with the attached sample files:

    diff -up one.txt two.txt | iconv -f UTF-8 -t UTF-8 > /dev/null

You will see

    iconv: illegal input sequence at position 151

ProblemType: Bug
DistroRelease: Ubuntu 11.10
Package: diff 1:3.0-1
ProcVersionSignature: Ubuntu 3.0.0-14.23-generic 3.0.9
Uname: Linux 3.0.0-14-generic i686
ApportVersion: 1.23-0ubuntu4
Architecture: i386
Date: Mon Dec 12 18:47:04 2011
EcryptfsInUse: Yes
InstallationMedia: Ubuntu 9.10 "Karmic Koala" - Release i386 (20091028.5)
PackageArchitecture: all
ProcEnviron:
 LANGUAGE=lt_LT:lt:en_GB:en
 LC_CTYPE=lt_LT.UTF-8
 PATH=(custom, user)
 LANG=lt_LT.UTF-8
 SHELL=/bin/bash
SourcePackage: diffutils
UpgradeStatus: Upgraded to oneiric on 2011-10-13 (59 days ago)