I figure there's no point in reporting this in bugzilla since F13 is EOL, but I figure it's worth mentioning here for those that still have to use F13 on ARM.

/usr/include/linux/netfilter/xt_CHECKSUM.h appears to be missing from kernel-headers-2.6.34.9-69.fc13.armv5tel. This makes some versions of iptables fail to build.

Gordan