Revert r330897:

This was intended to be a non-functional change. It wasn't. The commit
message was thus wrong. In addition it broke arm, and merged crypto
related code.

Revert with prejudice.

This revert skips files touched in r316370 since that commit was since
MFCed. This revert also skips files that require $FreeBSD$ property
changes.

Thank you to those who helped me get out of this mess including but not
limited to gonzo, kevans, rgrimes.

Requested by: gjb (re)

Partial merge of the SPDX changes

These changes are incomplete but are making it difficult
to determine what other changes can/should be merged.

No objections from: pfg

Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Make cu/tip handle when $HOME is not set in the environment.

Approved by: philip
Submitted by: ale
PR: bin/108775

Fix compilation warnings (up to level 3).

Resolve merge conflicts.

Use a proper protoype to declare interp() and move it to tip.h. Fix an
invocation with a wrong number of arguments.

Approved by: das (mentor)

make prototpyes match functions, and declare things static as needed

Fix merge conflicts, and because this still has a zillion warnings,
protect the build with a WARNS=2.

Fix the build.

#include <errno.h> where needed. Kill extern int errno;.

Minor warnings in tip corrected.

$Id$ -> $FreeBSD$

Some 64bit portability fixes.

Add prototypes, usage(). Use err(3).

Remove trailing whitespace.

Tom Gray's new tip changes to support a modem capabilities database and
fixes to many assorted bugs and misfeatures.
Submitted by: Tom Gray - DCA <dcasba@rain.org>