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

No need to support UL_GETSIZE and UL_SETSIZE anymore; they are about to be
renamed in RELENG_5_0.

Rename UL_GETSIZE to UL_GETFSIZE and UL_SETSIZE to UL_SETFSIZE; these are
the names required by 1003.1-2001. The old names are retained for
source compatibility with FreeBSD 5.0 and will be removed before 6.0.

Bracket the prototype for ulimit() with __BEGIN_DECLS/__END_DECLS
so that it can be called from C++.

Implement POSIX.1-2001 (XSI)'s ulimit(3).

Submitted by: Kyle Martin <mkm@ieee.org>