sbin: Automated cleanup of cdefs and other formatting

Apply the following automated changes to try to eliminate
no-longer-needed sys/cdefs.h includes as well as now-empty
blank lines in a row.

Remove /^#if.*\n#endif.*\n#include\s+<sys/cdefs.h>.*\n/
Remove /\n+#include\s+<sys/cdefs.h>.*\n+#if.*\n#endif.*\n+/
Remove /\n+#if.*\n#endif.*\n+/
Remove /^#if.*\n#endif.*\n/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/types.h>/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/param.h>/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/capsicum.h>/

Sponsored by: Netflix

Remove $FreeBSD$: one-line .c pattern

Remove /^[\s*]*__FBSDID\("\$FreeBSD\$"\);?\s*\n/

spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD

The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch
up to that fact and revert to their recommended match of BSD-2-Clause.

Discussed with: pfg
MFC After: 3 days
Sponsored by: Netflix

fusefs: use the fsname mount option if set

The daemon can specify fsname=XXX in its mount options. If so, the file
system should report f_mntfromname as XXX during statfs. This will show
up in the output of commands like mount and df.

Submitted by: Ali Abdallah <ali.abdallah@suse.com>
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D35090

mount_fusefs: fix a segfault on memory allocation failure

Reported by: Coverity
Coverity CID: 1354188
MFC after: 4 days
Sponsored by: The FreeBSD Foundation

fusefs: add a intr/nointr mount option

FUSE file systems can optionally support interrupting outstanding
operations. However, the file system does not identify to the kernel at
mount time whether it's capable of doing that. Instead it signals its
noncapability by returning ENOSYS to the first FUSE_INTERRUPT operation it
receives. That's a problem for reliable signal delivery, because the kernel
must choose which thread should get a signal before it knows whether the
FUSE server can handle interrupts. The problem is even worse because the
FUSE protocol allows a file system to simply ignore all FUSE_INTERRUPT
operations.

Fix the signal delivery logic by making interruptibility an opt-in mount
option. This will require a corresponding change to libfuse, but not to
most file systems that link to libfuse.

Bump __FreeBSD_version due to the new mount option.

Sponsored by: The FreeBSD Foundation

[skip ci] update copyright headers in fusefs files

Sponsored by: The FreeBSD Foundation

fusefs: enable write clustering

Enable write clustering in fusefs whenever cache mode is set to writeback
and the "async" mount option is used. With default values for MAXPHYS,
DFLTPHYS, and the fuse max_write mount parameter, that means sequential
writes will now be written 128KB at a time instead of 64KB.

Also, add a regression test for PR 238565, a panic during unmount that
probably affects UFS, ext2, and msdosfs as well as fusefs.

PR: 238565
Sponsored by: The FreeBSD Foundation

mount_fusefs(8): fix inverted condition check from r347544

Sponsored by: The FreeBSD Foundation

fusefs: reap dead sysctls

Remove the "sync_unmount" and "init_backgrounded" sysctls and the associated
options from mount_fusefs. Add no backwards-compatibility hidden options to
mount_fusefs because these options never had any effect, and are therefore
unlikely to be used.

Sponsored by: The FreeBSD Foundation

Rename fuse(4) to fusefs(4)

This makes it more consistent with other filesystems, which all end in "fs",
and more consistent with its mount helper, which is already named
"mount_fusefs".

Reviewed by: cem, rgrimes
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D19649

various: general adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

No functional change intended.

Make the "automounted" flag work for FUSE filesystems.

PR: 192852
Submitted by: taku at tackymt.homeip.net (earlier version)
MFC after: 1 month
Sponsored by: The FreeBSD Foundation

Fix warnings found by -Wmising-variable-declarations.

This self-written compiler warning, which is hopefully going to be
committed into LLVM sources soon, warns about potentially missing
`static' keywords, similar to -Wmissing-prototypes.

- bin/pax: Move external declaration of chdname and s_mask into extern.h.
- bin/setfacl: Move setfacl.c-specific stuff out of setfacl.h.
- sbin/mount_fusefs: Remove char *progname; use getprogname().
- others: add `static' where possible.

getopt_long() returns an int. Use the return value accordingly.

Pointy hat to: me
MFC after: 2 months
X-MFC: r241519,241521

Import a FreeBSD port of the FUSE Linux module.
This has been developed during 2 summer of code mandates and being revived
by gnn recently.
The functionality in this commit mirrors entirely content of fusefs-kmod
port, which doesn't need to be installed anymore for -CURRENT setups.

In order to get some sparse technical notes, please refer to:
http://lists.freebsd.org/pipermail/freebsd-fs/2012-March/013876.html

or to the project branch:
svn://svn.freebsd.org/base/projects/fuse/

which also contains granular history of changes happened during port
refinements. This commit does not came from the branch reintegration
itself because it seems svn is not behaving properly for this functionaly
at the moment.

Partly Sponsored by: Google, Summer of Code program 2005, 2011
Originally submitted by: ilya, Csaba Henk <csaba-ml AT creo DOT hu >
In collabouration with: pho
Tested by: flo, gnn, Gustau Perez,
Kevin Oberman <rkoberman AT gmail DOT com>
MFC after: 2 months