Fix aliasing bug causing in_cksum() to fail on odd packet sizes due to compiler optimization.
Fix aliasing bug causing in_cksum() to fail on odd packet sizes
due to compiler optimization.

PR:		bin/13292
Suggested by:	wollman

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase