libidn failing to build (configure.ac error)

[David Brownlee <abs%NetBSD.org@localhost>]

        With the latest pkgsrc tree libidn is failing to build for me
        on NetBSD/i386 5.0.

        The configure phase seems to run fine, then most of the build,
        but if fails in its 'doc' subdir.

configure.ac: no proper invocation of AM_INIT_AUTOMAKE was found.
configure.ac: You should verify that configure.ac invokes AM_INIT_AUTOMAKE,
configure.ac: that aclocal.m4 is present in the top-level directory,
configure.ac: and that aclocal.m4 was recently regenerated (using
aclocal).
doc/Makefile.am:20: ENABLE_GTK_DOC does not appear in AM_CONDITIONAL
doc/Makefile.am:27: required file `doc/mdate-sh' not found
doc/Makefile.am:27:   `automake --add-missing' can install `mdate-sh'
doc/Makefile.am:27: required file `doc/texinfo.tex' not found
doc/Makefile.am:27:   `automake --add-missing' can install `texinfo.tex'

        gtk-doc is installed, and adding ../../textproc/gtk-doc/buildlink3.mk
        doesn't seem to affect the result.

        Full build log at http://mono.org/abs/libidn.log

        Is anyone else seeing this?

        Thanks