Copy stable/10@r272459 to releng/10.1 as part of
the 10.1-RELEASE process.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

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

Sync licenses and the corresponding RCS IDs with NetBSD, mainly switching
the licenses of Matthew R. Green and the TNF to 2-clause.

Obtained from: NetBSD

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)

<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>.