virstor: remove relation between chunk size and MAXPHYS

There's no reason why the virstor chunk size needs to relate to MAXPHYS.
Remove it. Instead, just make sure that the chunk size is a multiple of
the sector size.

Reviewed by: imp
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D45518

virstor: write large maps in chunks during label

During the initial label of a virstor device, write out the allocation
map in chunks if it is large (> 1 MB) in order to avoid large mallocs.

Even though the kernel virstor geom may still do a large malloc to
represent the allocation map, this may still be useful to avoid a
ulimit.

Reviewed by: markj
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D45517

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spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD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

libgeom(3): Use calloc instead of malloc and bzero.

Pull Request: https://github.com/freebsd/freebsd-src/pull/546
MFC after: 1 week
Sponsored by: NVIDIA Networking

Normalize the g(eom,cache,part,...) build.

Rather then combining hardlink creation for the geom(8) binary with
shared library build, move libraries to src/lib/geom so they are
built and installed normally. Create a common Makefile.classes
which is included by both lib/geom/Makefile and sbin/geom/Makefile
so the symlink and libraries stay in sync.

The relocation of libraries allows libraries to be build for 32-bit
compat. This also reduces the number of non-standard builds in
the system.

This commit is not sufficent to run a 32-bit /sbin/geom on a 64-bit
system out of the box as it will look in the wrong place for libraries
unless GEOM_LIBRARY_PATH is set appropriatly in the environment.

Reviewed by: bdrewery
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D15360