replace some "goto xxx" with return(-1). (mostly cosmetic)
(PR#1404). Things to be noted: - all IP addresses are now `struct in_addr's. - the function rarp_getipaddress() no longer return `myip'; in stead it returns -1 on failure (errno set), 0 on success. `myip' is set as a size-effect.
Get rid of some more compiler warnings. Set errno where appropriate.