I emerged net-snmp-5.1.1-r1 with the lm_sensors use flag, and an snmpwalk produces no sensors output. After some investigation, I discovered the hw_sensors MIB module tries to dlopen libsensors.so.2, but in the current version of lm_sensors (2.8.7) this is libsensors.so.3. As a quick work-around I symlinked /usr/lib/libsensors.so.2 to libsensors.so.3. After restarting snmpd the sensors output is present. Maybe the net-snmp-lm_sensors.patch should dlopen libsensors.so instead of specifying a version? No warning or error output is produced when the library can't be opened, it just silently fails and ignores the module.
fixed in portage... thanks!
