automake19: texinfo error during build

[Jesse Sheidlower]

I'm trying to upgrade my automake from 1.8.5_2 to 1.9.6 (in
order to install Subversion, which seems to require
this). During the build, I get a screenful of errors like

./automake19.texi:8788: Unknown command `tie'.
./automake19.texi:8788: Misplaced {.
./automake19.texi:8788: Misplaced }.
./automake19.texi:9090: Unknown command `tie'.
[...]

before dying with

---
makeinfo: Removing output file `./automake19.info' due to errors; use --force to preserve.
*** Error code 2

Stop in /usr/ports/devel/automake19/work/automake-1.9.6/doc.
*** Error code 1

Stop in /usr/ports/devel/automake19/work/automake-1.9.6.
*** Error code 1

Stop in /usr/ports/devel/automake19.
** Command failed [exit code 1]: /usr/bin/script -qa /tmp/portupgrade39976.0 make
** Fix the problem and try again.
** Listing the failed packages (*:skipped / !:failed)
        ! devel/automake19 (automake-1.8.5_2)   (texinfo error)
---

I think my dependencies are up to date. Oh, this is on 4.X.  I
didn't see anything relevant from Googling. What do I need to
fix to get this in order?

Thanks.

Jesse Sheidlower