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

/* -> /*- for license, add FreeBSD tag

Remove old files no longer needed.
Add new files created for emulator.
Modify NetBSD import to work with FreeBSD and add new features and
code. The complete emulator is essentially a combination of work/code
implemented by Sean Eric Fagan, Soren Schmidt, Scott Bartram, and myself,
Steven Wallace.

Features of this new emulator system include:

o "clean" code, including strict prototyping.
o Auto-generation of ibcs2 system calls, xenix system calls, isc system
calls. Generation includes system tables, structure definitions,
and prototyping of function calls.
o ibcs2 emulator does not rely on any COMPAT_43 system calls.
o embedded socksys support
o ibcs2 msgsys, semsys, shmsys calls supported if supported in kernel
o alternate /emul/ibcs2 namespace searched first for files in ibcs2
system. Usefull to keep sysv libraries, binaries in /emul/ibcs2.
o many other finer details and functions fixed or implemented.

This commit was generated by cvs2svn to compensate for changes in r11394,
which included commits to RCS files with non-trunk default branches.

Import of original NetBSD's ibcs2 emulator sources by Scott Bartram,
which is used as a basis for a more complete and cleaner ibcs2 emulator.
(snapshot about May 1995 with a few files from September 1995)

Some files and code from old emulator still remains.
New files, features, and changes have been implemented by myself,
which will be shown in following commits.