./configure --enable-ipf-transparent

Hi all,
Where is configure find IP-Filter header files ?
I have it by path /usr/include/netinet/ip_compat.h etc *h
When I configure with --enable-ipf-transparent
He not find here that it has told me

----
checking if IP-Filter header files are installed... no
WARNING: Cannot find necessary IP-Filter header files
         Transparent Proxy support WILL NOT be enabled
---
What is problem ? (SquidPatch2 on Solaris2.5)
Can who prompt where to correct configure or .?.. to path
/usr/include/netinet/ip_compat.h etc *h ?
Any ideas welcome.
With best, Dan