andypugh@raspberrypi ~/git/rpi-linux $ make modules
  CHK     include/config/kernel.release
  CHK     include/generated/uapi/linux/version.h
  CHK     include/generated/utsrelease.h
make[1]: 'include/generated/mach-types.h' is up to date.
  CALL    scripts/checksyscalls.sh
  CC [M]  net/ipv4/ip_tunnel.o
  CC [M]  net/ipv4/ipip.o
  CC [M]  net/ipv4/gre_demux.o
  LD [M]  net/ipv4/gre.o
  CC [M]  net/ipv4/ip_gre.o
  CC [M]  net/ipv4/udp_tunnel.o
  CC [M]  net/ipv4/ah4.o
  CC [M]  net/ipv4/esp4.o
  CC [M]  net/ipv4/ipcomp.o
  CC [M]  net/ipv4/xfrm4_tunnel.o
  CC [M]  net/ipv4/xfrm4_mode_beet.o
  CC [M]  net/ipv4/inet_lro.o
  CC [M]  net/ipv4/tunnel4.o
  CC [M]  net/ipv4/xfrm4_mode_transport.o
  CC [M]  net/ipv4/xfrm4_mode_tunnel.o
  CC [M]  net/ipv4/inet_diag.o
  CC [M]  net/ipv4/tcp_diag.o
  LD [M]  net/ipv4/netfilter/nf_conntrack_ipv4.o
  LD [M]  net/ipv4/netfilter/nf_nat_ipv4.o
  CC [M]  net/ipv4/netfilter/ipt_ECN.o
net/ipv4/netfilter/ipt_ECN.c: In function ‘set_ect_ip’:
net/ipv4/netfilter/ipt_ECN.c:33:18: error: ‘XT_DSCP_MASK’ undeclared (first use in this function)
net/ipv4/netfilter/ipt_ECN.c:33:18: note: each undeclared identifier is reported only once for each function it appears in
net/ipv4/netfilter/ipt_ECN.c: In function ‘ecn_tg_check’:
net/ipv4/netfilter/ipt_ECN.c:105:23: error: ‘XT_DSCP_MASK’ undeclared (first use in this function)
scripts/Makefile.build:263: recipe for target 'net/ipv4/netfilter/ipt_ECN.o' failed
make[3]: *** [net/ipv4/netfilter/ipt_ECN.o] Error 1
scripts/Makefile.build:402: recipe for target 'net/ipv4/netfilter' failed
make[2]: *** [net/ipv4/netfilter] Error 2
scripts/Makefile.build:402: recipe for target 'net/ipv4' failed
make[1]: *** [net/ipv4] Error 2
Makefile:937: recipe for target 'net' failed
make: *** [net] Error 2