Fix for 'tcpconns.c: linux/inet_diag.h : No such file or directory'

Hello,

This commit (6246d325447713539a3962dac2ad8eda0f8a9094) contains a new fix for compilation failure with old Linux kernels (including 2.6.9 in RHEL 4).

The problem : 

    tcpconns.c:77:30: linux/inet_diag.h : No such file or directory

And other errors like NETLINK_INET_DIAG undeclared... because of this missing header.

Regards,
Yves