I'm attaching a log with this error shown... It's perfectly reproducible on
NetBSD-6.1.3/amd64 with pkgsrc-2014Q1 (the snapshot of pkgsrc is available
here: https://github.com/krytarowski/pkgsrc-2014Q1 -- however it's still
upstream, unmodified version, fetched from ftp.netbsd.org)
I've encountered the same problem with www/firefox, with the same solution
(rename autoconf to autoconf-2.13).
If USE_TOOLS autoconf213 is supposed to resolve it, then I don't really
understand it. I will try to validate the linkage.
I use a clean system, without any pkgsrc version installed before. I'm also
working in the --unprivileged mode. My mk.conf doesn't contain any related
entries (maybe just MAKE_JOBS=8, but it problably doesn't matter).