Error in compiling with russian support

[Lev Butyrev]

Hi. Sorry for my bad english.

Compilation bogofilter 0.94.12 close with error:

gcc -DBOGOFILTER  -g -O2  -Wpointer-arith -ggdb -Wall -W 
-Wstrict-prototypes -Wmissing-prototypes -Wshadow -Wbad-function-cast 
-Wcast-qual -Wcast-align -Wwrite-strings -Waggregate-return 
-Wmissing-declarations -Wmissing-format-attribute -Wnested-externs 
-fno-common -Wchar-subscripts -Wcomment -Wimplicit -Wsequence-point 
-Wreturn-type -Wno-system-headers -Wformat   -o bogofilter  bogofilter.o 
main.o libbogofilter.a    strlcpy.o strlcat.o -ldb  libbf_gsl.a -lm
libbogofilter.a(lexer.o)(.text+0x666): In function `yyinput':
/usr/src/bogofilter/bogofilter-0.94.12/src/lexer.c:330: undefined 
reference to `htmlUNICODE_decode'
collect2: ld returned 1 exit status

Compilation bogofilter 0.92.8 finished without errors.
distributive slackware
gcc version 3.3.4
glibc-2.3.4
glibc-i18n-2.3.4

Do I have to upgrade glibc?