configure could not find ipfilter header files!!!

hello, the squid configure script could not find the header files...
if I am right they are these files right?
why does not it able to find them?
thanks

PS. I have searched mailing list for this error but I could not find
anything...yet...

suomi:/root/programs/sources/squid/squid-2.1.PATCH2#locate ip_compat.h
/usr/include/netinet/ip_compat.h
suomi:/root/programs/sources/squid/squid-2.1.PATCH2#locate ip_fil.h
/usr/include/netinet/ip_fil.h
suomi:/root/programs/sources/squid/squid-2.1.PATCH2#locate ip_nat.h
/usr/include/netinet/ip_nat.h
Received on Wed Feb 24 1999 - 12:11:59 MST