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

Adjust the syscall stub macros to be consistent in their meaning. In
particular:
SYSCALL() makes a syscall, with errno handling, and continues execution
directly after the macro in the non-error case.
RSYSCALL() is just like SYSCALL(), but returns after success.
Both SYSCALL(name) and RSYSCALL(name) export "__sys_name" as a strong
symbol, with "_name" and "name" as weak aliases.
PSEUDO() is just like RSYSCALL(), but skipping the "name" weak alias. It
still does "__sys_name" and "_name".

Change i386 to add errno handling to PSEUDO. The same for amd64 and
sparc64, with appear to have copied the behavior.
ia64 was correct (as was alpha). Just remove some apparently unused
variants of the macros. (untested!)
I believe powerpc is correct.
Fix arm to not export "name" from the PSEUDO case. Remove apparently
extra unused variants. (untested!)

The errno problem manifested on i386/amd64/sparc64 by having "PSEUDO"
classified syscalls return without setting errno. eg: "addr = mmap()"
could return with "addr" = 22 instead of setting errno to 22 and
returning -1.

Approved by: re (kensmith)

Per Regents of the University of Calfornia letter, remove advertising
clause.

# If I've done so improperly on a file, please let me know.

Fix the style of the SCM ID's.
I believe have made all of libc .h's as consistent as possible.

Include utrap.h for soft trap types.

Add .type and .size pseudo-ops to system call macros so that dynamic binaries
will link. They must be used for weak symbols as well as strong ones.

Minimal libc for sparc64.

Reviewed by: obrien