OVS_GREP_IFELSE([$KSRC26/include/linux/skbuff.h], [skb_cow_head])
OVS_GREP_IFELSE([$KSRC26/include/linux/skbuff.h], [skb_transport_header],
[OVS_DEFINE([HAVE_SKBUFF_HEADER_HELPERS])])
OVS_GREP_IFELSE([$KSRC26/include/linux/skbuff.h], [skb_cow_head])
OVS_GREP_IFELSE([$KSRC26/include/linux/skbuff.h], [skb_transport_header],
[OVS_DEFINE([HAVE_SKBUFF_HEADER_HELPERS])])