FreeBSD:4.1b1 - 'daylight' undeclared

While trying to make w3c-libwww-4.1b1 Library sources under FreeBSD
2.1R(+), I get the following:

gcc -c -DHAVE_CONFIG_H -I. -I. -I../..   -g -O HTInet.c

HTInet.c: In function `HTGetTimeZoneOffset':

HTInet.c:528: `daylight' undeclared (first use this function)


Is this a known problem?  I haven't found "daylight" in standard nor
libwww headers.