gnome-core-0.13 compile problem

[Bucephalus <allen kesmai com>]

On an up-to-date RH5.0/Intel system:

gcc -g -O2 -Wall -o gnome-help-browser gnome-helpwin.o
gnome-help-browser.o toc2.o toc2-man.o toc2-ghelp.o toc2-info.o docobj.o
mime.o transport.o HTParse.o cache.o parseUrl.o queue.o history.o misc.o
window.o visit.o magic.o bookmarks.o -L/usr/local/lib -lgnomeui -lgnome
-lgnomesupport -ldl -lgdk_imlib -ltiff -lgif -ljpeg -lpng -lz -lgtk -lgdk
-lglib -lm -L/usr/X11R6/lib -lSM -lICE -lX11 -lXext -lgtkxmhtml -lgtk
-lgdk -lglib -lm -lXpm -ljpeg -lpng -lz -L/usr/X11R6/lib -lSM -lICE -lX11
-lXext
misc.o: In function `loadFileToBuf':
/usr/local/src/gnome-core-0.13/help-browser/misc.c:145: undefined
reference to `gzopen'
/usr/local/src/gnome-core-0.13/help-browser/misc.c:148: undefined
reference to `gzread'
/usr/local/src/gnome-core-0.13/help-browser/misc.c:157: undefined
reference to `gzread'
/usr/local/src/gnome-core-0.13/help-browser/misc.c:159: undefined
reference to `gzclose'
make[2]: *** [gnome-help-browser] Error 1
make[2]: Leaving directory `/usr/local/src/gnome-core-0.13/help-browser'
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory `/usr/local/src/gnome-core-0.13'
make: *** [all-recursive-am] Error 2
root@gnosis:/usr/local/src/gnome-core-0.13$ 

Any ideas?

Many thanks,
-Allen Gooch