cd /usr/ports
portupgrade devel/automake19
実行すると

===> Building for automake-1.9.6_2
Making all in .
省略

Making all in doc
restore=: && backupdir=".am$$" && am__cwd=
`pwd` && cd . && rm -rf $backupdir && mkdir
$backupdir && if (makeinfo --no-split --version)
>/dev/null 2>&1; then for f in ./automake-1.9.info
./automake-1.9.info-[0-9] ./automake-1.9.info-[0-9][0-9]
./automake-1.9.i[0-9] ./automake-1.9.i[0-9][0-9];
do if test -f $f; then mv $f $backupdir; restore=mv;
else :; fi; done; else :; fi && cd "$am__cwd";
if makeinfo --no-split -I . -o ./automake-1.9.info
./automake-1.9.texi; then rc=0; cd .; else
rc=$?; cd . && $restore $backupdir/* `echo
"././automake-1.9.info" | sed 's|[^/]*$||'`; fi;
rm -rf $backupdir; exit $rc
./automake-1.9.texi:9821: Unknown command `headitem'.
makeinfo: Removing output file `./automake-1.9.info'
due to errors; use --force to preserve.
*** Error code 1

これってどうすれば良いですか？