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

Reorganize wrapper around setrunelocale() to mark it as deprecated
in FreeBSD 6

Reduce code duplication by separating _PathLocle detection code into
internal helper function.

style(9)'ify

Restore PATH_LOCALE functionality using issetugid() call now

Do Andrey's homework :) before merging this into 2.2:

. add idempotency #ifdef
. avoid sloppy common-style external declaration.

Use symbolic constants instead of hardcoded digits
Add range check for setrunelocale since it can be called
directly.
Remove _startup_setlocale compatibility function

Should go into 2.2