Feature #796 introduced a feature that is not supported by older versions of `libpcap. Need to detect and support older versions.

To Reproduce
Steps to reproduce the behavior:

1. In my dev environment I start an older bigendian ppc image and compile. It fails.

Expected behavior
Expect build to work, and that timestamps are properly handled throught the system.

System (please complete the following information):

• OS: Linux
• OS version: PPC
• Tcpreplay Version 4.5.0