MFC r312105,r312162:

MFC r312105,r312162:

r312105:

Conditionalize libwrap support into inetd based on MK_TCP_WRAPPERS

This will allow inetd to stand by itself without libwrap.

Relnotes:	yes

r312162:

Fix up r312105

- Only #include tcpd.h when LIBWRAP is true to avoid header include errors
- Only define whichaf when LIBWRAP is true to avoid -Wunused warning and
  to avoid issues with structs being defined that should only be defined
  when tcpd.h is included.

Pointyhat to:	ngie

git-svn-id: svn://svn.freebsd.org/base/stable/10@313206 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f