sys: Remove ancient SCCS tags.

Remove ancient SCCS tags from the tree, automated scripting, with two
minor fixup to keep things compiling. All the common forms in the tree
were removed with a perl script.

Sponsored by: Netflix

sys: Remove $FreeBSD$: one-line .h pattern

Remove /^\s*\*+\s*\$FreeBSD\$.*$\n/

Reduce code duplication in machine/_types.h

Many of these typedefs are the same across all architectures or can
be set based on an architecture-independent compiler-provided macro
(e.g. __SIZEOF_SIZE_T__). These macros have been available since GCC 4.6
and Clang sometime before 3.0 (godbolt.org does not have any older clang
versions installed).

I originally considered using the compiler-provided `__FOO_TYPE__` directly.
However, in order to do so we have to check that those match the previous
typedef exactly (not just that they have the same size) since any change
would be an ABI break. For example, changing `long` to `long long` results
in different C++ name mangling. Additionally, Clang and GCC disagree on
the underlying type for some of (u)int*_fast_t types, so this change
only moves the definitions that are identical across all architectures
and does not touch those types.

This de-deduplication will allow us to have a smaller diff downstream in
CheriBSD: we only have to only change the (u)intptr_t definition in
sys/_types.h in CheriBSD instead of having to change machine/_types.h for
all CHERI-enabled architectures (currently RISC-V, AArch64 and MIPS).

Reviewed By: imp, kib
Differential Revision: https://reviews.freebsd.org/D29895

i386: Merge PAE and non-PAE pmaps into same kernel.

Effectively all i386 kernels now have two pmaps compiled in: one
managing PAE pagetables, and another non-PAE. The implementation is
selected at cold time depending on the CPU features. The vm_paddr_t is
always 64bit now. As result, nx bit can be used on all capable CPUs.

Option PAE only affects the bus_addr_t: it is still 32bit for non-PAE
configs, for drivers compatibility. Kernel layout, esp. max kernel
address, low memory PDEs and max user address (same as trampoline
start) are now same for PAE and for non-PAE regardless of the type of
page tables used.

Non-PAE kernel (when using PAE pagetables) can handle physical memory
up to 24G now, larger memory requires re-tuning the KVA consumers and
instead the code caps the maximum at 24G. Unfortunately, a lot of
drivers do not use busdma(9) properly so by default even 4G barrier is
not easy. There are two tunables added: hw.above4g_allow and
hw.above24g_allow, the first one is kept enabled for now to evaluate
the status on HEAD, second is only for dev use.

i386 now creates three freelists if there is any memory above 4G, to
allow proper bounce pages allocation. Also, VM_KMEM_SIZE_SCALE changed
from 3 to 1.

The PAE_TABLES kernel config option is retired.

In collaboarion with: pho
Discussed with: emaste
Reviewed by: markj
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D18894

Do not include float interfaces when using libsa.

We don't support float in the boot loaders, so don't include
interfaces for float or double in systems headers. In addition, take
the unusual step of spiking double and float to prevent any more
accidental seepage.

Move __va_list and related defines to sys/sys/_types.h

__va_list and related defines are identical in all the
ARCH/include/_types.h files. Move them to sys/sys/_types.h

Sponsored by: Netflix

Remove lint support from system headers and MD x86 headers.

Reviewed by: dim, jhb
Discussed with: imp
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D13156

spdx: initial adoption of licensing ID tags.

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.

Special thanks to Wind River for providing access to "The Duke of
Highlander" tool: an older (2014) run over FreeBSD tree was useful as a
starting point.

Initially, only tag files that use BSD 4-Clause "Original" license.

RelNotes: yes
Differential Revision: https://reviews.freebsd.org/D13133

Define the vm_ooffset_t and vm_pindex_t types as machine-independend.

The types are for the byte offset and page index in vm object. They
are similar to off_t, which is defined as 64bit MI integer. Using MI
definitions will allow to provide consistent MD values of vm
object-related maximum sizes.

Reviewed by: alc
Sponsored by: The FreeBSD Foundation
MFC after: 1 week

Add missing dependency on <machine/_limits.h>.

This header uses __INT_MIN and __INT_MAX, which is provided by
<machine/_limits.h>. This is needed to make <stdint.h>'s WCHAR_MIN and
WCHAR_MAX work without including other headers as well.

Fix more style issues.

Submitted by: bde

Fix style(9) bugs.

Always define __va_list for amd64 and restore pre-r232261 behavior for i386.
Note it allows exotic compilers, e.g., TCC, to build with our stdio.h, etc.

PR: 201749
MFC after: 1 week

Rename __wchar_t so it no longer conflicts with __wchar_t from clang 3.4
-fms-extensions.

MFC after: 2 weeks

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

Consitently use "__LP64__".
[there are 33 __LP64__'s in the kernel (minus cddl/ and contrib/),
and 11 _LP64's]

Copy amd64 _types.h to x86 and merge with i386 _types.h. Replace existing
amd64/i386/pc98 _types.h with stubs.