While I was looking at the code and options to pull this into SmallWall I noticed some potential problems in the .configure options.
First, whitespace is inconsistent, and in one case, missing. So at some point in the future "--with-sys-location="location"--without-openssl" may get silently dropped.
Second, --with-default-snmp-version="2" is set twice.
I cleaned it up to make it easier to parse and read, and this is what is in SmallWall. Please feel free to use my trivial, but potentially helpful later, changes.

# ucd-snmp
cd $MW_BUILDPATH/tmp
rm -Rf net-snmp-5.7.3
tar -zxf $MW_BUILDPATH/freebsd8/build/local-sources/net-snmp-5.7.3.tar.gz
cd net-snmp-5.7.3
./configure --with-default-snmp-version="2" --with-sys-contact="contact" \
--with-sys-location="location" --without-openssl --enable-ipv6 \
--disable-set-support --disable-des --disable-privacy --disable-md5 \
--disable-debugging --enable-static --enable-mini-agent \
--disable-testing-code --disable-shared-version --disable-shared \
'--with-out-transports=TCP Unix TCPIPv6 Callback' --enable-mfd-rewrites \
'--with-mib-modules=if-mib host mibII/var_route ucd_snmp' --with-defaults
make