tcpd: complete function prototypes.

This clears up at least a build issues on mysql-server
ports. While here also replace some spaces with tabs
in our headers.

PR:		42336
MFC after:	2 weeks


git-svn-id: svn+ssh://svn.freebsd.org/base/head@272949 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f