buildworld failure: "don't know how to make thr_atfork.c"

CVSup'd today [Wed Nov  5 17:15:14 CST 2003] and buildworld fails.

$ make buildworld

.....

===> lib/libpcap
yacc -d -p pcapyy -o grammar.c /usr/src/lib/libpcap/../../contrib/libpcap/grammar.y
ln -sf grammar.h tokdefs.h
lex -t  -Ppcapyy /usr/src/lib/libpcap/../../contrib/libpcap/scanner.l > scanner.c
sed 's/.*/char pcap_version[] = "&";/' /usr/src/lib/libpcap/../../contrib/libpcap/VERSION > version.c
rm -f .depend
mkdep -f .depend -a    -DHAVE_CONFIG_H -Dyylval=pcapyylval -I/usr/src/lib/libpcap -I. -DINET6 -I/usr/src/lib/libpcap/../../contrib/libpcap  grammar.c /usr/src/lib/libpcap/../../contrib/libpcap/pcap-bpf.c /usr/src/lib/libpcap/../../contrib/libpcap/pcap.c /usr/src/lib/libpcap/../../contrib/libpcap/inet.c /usr/src/lib/libpcap/../../contrib/libpcap/gencode.c /usr/src/lib/libpcap/../../contrib/libpcap/optimize.c /usr/src/lib/libpcap/../../contrib/libpcap/nametoaddr.c /usr/src/lib/libpcap/../../contrib/libpcap/etherent.c /usr/src/lib/libpcap/../../contrib/libpcap/savefile.c /usr/src/lib/libpcap/../../contrib/libpcap/bpf/net/bpf_filter.c /usr/src/lib/libpcap/../../contrib/libpcap/bpf_image.c /usr/src/lib/libpcap/../../contrib/libpcap/bpf_dump.c scanner.c version.c
===> lib/libpthread
make: don't know how to make thr_atfork.c. Stop
*** Error code 2

Stop in /usr/src/lib.
*** Error code 1

Stop in /usr/src.
*** Error code 1

Stop in /usr/src.
*** Error code 1

Stop in /usr/src.
*** Error code 1

Stop in /usr/src.

 - aW