another one in Solaris' port-protos.h.

The following patch will bring inet_aton's prototype into scope for
Ultrix to silence a compilation warning.

If the intention is to have inet_aton's prototype in its own header
filer, the declaration in Solaris' port-protos.h should be removed.
If the declaration in port-protos.h is deemed to be the correct
place, a declaration should be added in Ultrix' port-protos.h

regards
Erik Bertelsen