Need help getting netwatch in netdiag to build on woody

[Robert Woodcock <rcw@debian.org>]

[please cc: me on replies - I'm not subscribed]

Hello, today I tried rebuilding netdiag after fixing #74408.

To my non-surprise, netwatch didn't build:

netwatch.c:227: sizeof applied to an incomplete type
netwatch.c:244: sizeof applied to an incomplete type
netwatch.c:430: sizeof applied to an incomplete type
netwatch.c: In function `dokeyin':
netwatch.c:3045: sizeof applied to an incomplete type

Line 226-227 are:
#define IPOPTSIZE (sizeof(struct ip_options))
int ipoptsz = IPOPTSIZE;

This same code compiles fine on potato - I'm reasonably sure it's the
new libc development headers that are more picky about this.

So, what's the correct way to get sizeof(struct ip_options)?

FYI, the other instances are more of the same:

244:
#define SN_RCV_BUF_SIZE (sizeof(struct ether_head)+ \
                                 sizeof(struct ip)+ \
                                 sizeof(struct ip_options)+ \
                                 sizeof(struct tcphdr)+4)
#define SN_RCV_BIGBUFSIZE SN_RCV_BUF_SIZE+80
int sn_rcv_bufsize = SN_RCV_BIGBUFSIZE;

430:
unsigned char buf[SN_RCV_BIGBUFSIZE + 20];

3045:
sn_rcv_bufsize = SN_RCV_BIGBUFSIZE;
-- 
Robert Woodcock - rcw@debian.org
"The Internet would be very orderly without the people."
	-- Esther Dyson, Board Chairman, ICANN