Net-snmp configuration

I'm trying to remove extra mibs from net-snmp. I'm doing it by modifying Makefile for net-snmp
(for example by removing if-mib and ip-mib MIB modules from SNMP_MIB_MODULES_INCLUDED and adding them to SNMP_MIB_MODULES_EXCLUDED), but the problem is that when I delete them snmpwalk fails on (probably) its OIDs. I thought that when I delete MIB module from net-snmp configuration, the related MIB simply dissapears, so what am I missing here? Why do I keep getting errors from snmpwalk?