Silence warnings with libshishi.
Begin adaptions to Heimdal's Kerberos.

Aim at an adaption of all r-commands, with the first
incomplete steps for `rsh'.
bootstrap: Updated from gnulib. (silent change)
libinetutils: Skeletal preparations for Heimdal.

Lay the foundation for separate authentication code to be
used by the r-commands when built with standard Kerberos5.