DIRDEPS_BUILD: Connect new directories.

This is a direct commit since MFCing these changes is impractical.

Sponsored by: Dell EMC Isilon

MFC r317385:

Clean up Makefile.

Prefer SRCTOP vs .CURDIR relative paths.

Find libnetbsd using LIBADD infrastructure rather than manual hackery.

Reviewed by: ngie, bapt
Obtained from: CheriBSD
Sponsored by: DARPA, AFRL

MFC r315640

Port the getaddrinfo(1) utility from NetBSD.

PR: 183148
Submitted by: Lohith Bellad <lohithbsd@gmail.com>
Obtained from: NetBSD
Relnotes: yes
Sponsored by: Dell EMC

Port the getaddrinfo(1) utility from NetBSD

Submitted by: Lohith Bellad <lohithbsd@gmail.com>
Reviewed by: hiren (earlier rev), ae
Obtained from: NetBSD
MFC after: 1 week
Relnotes: yes
Sponsored by: Dell EMC
Differential Revision: https://reviews.freebsd.org/D9365