I just built the updated textproc/xmlto on a 7-RELEASE tinderbox and it failed to build.  I tested it 3 times with same results.  Ports are fully updated.

Here the end of the tinderbox log (can provide a link to the full log if needed):

configure: creating ./config.status
config.status: creating Makefile
config.status: creating xmlto
config.status: WARNING:  xmlto.in seems to ignore the --datarootdir setting
config.status: creating xmlto.spec
config.status: creating config.h
config.status: executing depfiles commands
===>  Building for xmlto-0.0.20
make  all-am
depbase=`echo xmlif/xmlif.o | sed 's|[^/]*$|.deps/&|;s|\.o$||'`; cc -DHAVE_CONFIG_H -I.      -O2 -fno-strict-aliasing -pipe -MT xmlif/xmlif.o -MD -MP -MF $depbase.Tpo -c -o xmlif/xmlif.o xmlif/xmlif.c && mv -f $depbase.Tpo $depbase.Po
cc  -O2 -fno-strict-aliasing -pipe   -o xmlif/xmlif xmlif/xmlif.o  
for xml in xmlif.xml xmlto.xml; do  FORMAT_DIR=./format  /usr/local/bin/bash ./xmlto -o man/man1 man ./doc/$xml ;  done || ( RC=$?; cat ./FAQ; exit $RC )
Note: meta source : No productname or alternative       xmlif
Note: meta source : No refmiscinfo@class=source         xmlif
Note: meta version: No productnumber or alternative     xmlif
Note: meta version: No refmiscinfo@class=version        xmlif
Note: meta manual : No ancestor with title              xmlif
Note: meta manual : No refmiscinfo@class=manual         xmlif
Note: Writing xmlif.1
Note: meta version: No productnumber or alternative     xmlto
Note: meta version: No refmiscinfo@class=version        xmlto
Note: Writing xmlto.1

Q: I'm trying to build xmlto on my Debian box, but it doesn't work.

A: If you get `Attempt to load network entity' errors when building
   xmlto, your system does not have the required support for XML
   Catalogs
   (http://www.oasis-open.org/committees/entity/spec-2001-08-06.html).
   In particular, Debian has no support for these.  Try the Fedora
   Project <http://fedoraproject.org>.
*** Error code 1

Stop in /work/a/ports/textproc/xmlto/work/xmlto-0.0.20.
*** Error code 1

Stop in /work/a/ports/textproc/xmlto/work/xmlto-0.0.20.
*** Error code 1

Stop in /a/ports/textproc/xmlto.
================================================================
build of /usr/ports/textproc/xmlto ended at Thu Apr 24 17:04:11 UTC 2008

How-To-Repeat: Build textproc/xmlto