Fix leak in libc NFSv4 ACL flags parsing

Free memory allocated by strdup() in parse_flags_verbose().

Submitted by: Andrew Walker <walker.aj325_gmail.com>
Reported by: valgrind
Reviewed by: allanjude, freqlabs, rpokala
Sponsored by: iXsystems, Inc.
Differential Revision: https://reviews.freebsd.org/D29871

(cherry picked from commit dd559118ab3f065ae230b324c3fe4bb1c9b7ca56)

Git Hash: 550fcd830db7e8d644795e5fc9bd83ef4604a1c1
Git Author: walker.aj325_gmail.com

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

libc: replace 0 with NULL for pointers.

While here also cleanup some surrounding code; particularly
drop some malloc() casts.

Found with devel/coccinelle.

Reviewed by: bde (previous version - all new bugs are mine)

Expose an interface to determine if an ACE is inherited.

Submitted by: sef
Reviewed by: trasz
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D3540

Make it possible to use permission sets (full_set, modify_set, read_set
and write_set) with setfacl(1).

PR: kern/154113
Submitted by: Shawn Webb <lattera at gmail dot com> (earlier version)
MFC after: 1 month

Fix c194955 - somehow I managed all the new files, tripling their
contents.

Add NFSv4 ACL support to libc.

This adds the following functions to the acl(3) API: acl_add_flag_np,
acl_clear_flags_np, acl_create_entry_np, acl_delete_entry_np,
acl_delete_flag_np, acl_get_extended_np, acl_get_flag_np, acl_get_flagset_np,
acl_set_extended_np, acl_set_flagset_np, acl_to_text_np, acl_is_trivial_np,
acl_strip_np, acl_get_brand_np. Most of them are similar to what Darwin
does. There are no backward-incompatible changes.

Approved by: rwatson@