Arch Linux

Ok Judd, I figured out what was going on.

There's a sed hack in the iptables PKGBUILD:
sed -i "s:/usr/src/linux:/usr/src/linux*:" Makefile

which was causing my builds to use existing full kernel sources to complete the compile.
(It was picking up ipt_CLUSTERIP.c from a full copy of 2.6.12.3 I had in /usr/src).

I think that sed line can be dropped, since KERNEL_DIR is set on the make line below it,
but KERNEL_DIR should also be specified on the 2 make lines below the main one... (I think
CLUSTERIP was building during my "make install").

the kernel26 package needs to be modified to include net/ipv4/netfilter/ipt_CLUSTERIP.c in order
for clusterip support to be built when iptables is compiled.