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

ARM: Remove trailing whitespace from sys/arm/include
No functional changes.

Approved by: kib (mentor)

Make the wchar_t type machine dependent.

This is required for ARM EABI. Section 7.1.1 of the Procedure Call for the
ARM Architecture (AAPCS) defines wchar_t as either an unsigned int or an
unsigned short with the former preferred.

Because of this requirement we need to move the definition of __wchar_t to
a machine dependent header. It also cleans up the macros defining the limits
of wchar_t by defining __WCHAR_MIN and __WCHAR_MAX in the same machine
dependent header then using them to define WCHAR_MIN and WCHAR_MAX
respectively.

Discussed with: bde

On mixed 32/64 bit architectures (mips, powerpc) use __LP64__ rather than
architecture macros (__mips_n64, __powerpc64__) when 64 bit types (and
corresponding macros) are different from 32 bit. [1]

Correct the type of INT64_MIN, INT64_MAX and UINT64_MAX.

Define (U)INTMAX_C as an alias for (U)INT64_C matching the type definition
for (u)intmax_t. Do this on all architectures for consistency.

Suggested by: bde [1]
Approved by: kib (mentor)

The NetBSD Foundation has granted permission to remove clauses 3 and 4.

Obtained from: NetBSD

<stdint.h> should define WINT_M{AX,IN} independent from whether WCHAR_MIN is
defined. Otherwise first including <wchar.h> and then <stdint.h> leads to no
WINT_M{AX,IN} at all.

PR: 64956
Approved by: das (mentor)

Create a new header <machine/_stdint.h> for storing MD parts of
<stdint.h>. Previously, parts were defined in <machine/ansi.h> and
<machine/limits.h>. This resulted in two problems:
(1) Defining macros in <machine/ansi.h> gets in the way of that
header only defining types.
(2) Defining C99 limits in <machine/limits.h> adds pollution to
<limits.h>.