libdtrace: Add kinst support

kinst does not instantiate its probes automatically, it only does so on
demand via an ioctl interface implemented by /dev/kinst. This change
modifies libdtrace to perform that work when the script references the
kinst provider, similar to the way pid provider probes are implemented.

Reviewed by: markj
MFC after: 3 months
Sponsored by: Google, Inc. (GSoC 2022)
Differential Revision: https://reviews.freebsd.org/D36852

Use PC-relative relocations for USDT probe sites on i386 and amd64.

When recording probe site addresses in the output DOF file, dtrace -G
needs to emit relocations for the .SUNW_dof section in order to obtain
the addresses of functions containing probe sites. DTrace expects the
addresses to be relative to the base address of the final ELF file,
and the amd64 USDT implementation was relying on some unspecified and
incorrect behaviour in the base system GNU ld to achieve this.

This change reimplements the probe site relocation handling to allow
USDT to be used with lld and newer GNU binutils. Specifically, it
makes use of R_X86_64_PC64/R_386_PC32 relocations to obtain the
probe site address relative to the DOF file address, and adds and uses a
new DOF relocation type which computes the final probe site address using
these relative offsets.

Reported by and discussed with: Rafael Espíndola
MFC after: 1 month
Differential Revision: https://reviews.freebsd.org/D9374

Mechanically convert cddl sun #ifdef's to illumos

Since the upstream for cddl code is now illumos not sun, mechanically
convert all sun #ifdef's to illumos #ifdef's which have been used in all
newer code for some time.

Also do a manual pass to correct the use if #ifdef comments as per style(9)
as well as few uses of #if defined(__FreeBSD__) vs #ifndef illumos.

MFC after: 1 month
Sponsored by: Multiplay

Adjust some checks missed in r274637, now that pi_rname can be NULL.

Additionally fix a misparenthesization in the same check, noticed while
fixing the first bug. This bug only appears to cause problems if the same
USDT probe appears twice within a static function.

X-MFC-With: r274637

DTrace imposes a 128-byte limit on the length of the function component of
a probe name. When dtrace -G builds up a DOF section for the specified
provider(s), the probe function names are truncated to fit in this limit.
The DOF is later used to build the symbol table for the generated object
file, so the table can end up with truncated references, causing link
errors.

Instead of potentially truncating symbol table entries, write the full
function name to the DOF string table and allow the kernel to enforce the
128-byte function name limit when a process attempts to load its DOF.

PR: 194757
Differential Revision: https://reviews.freebsd.org/D1175
Reviewed by: rpaulo
MFC after: 2 weeks

A new jail(8) with a configuration file, to replace the work currently done
by /etc/rc.d/jail.

Create the altix project branch. The altix project will add support
for the SGI Altix 350 to FreeBSD/ia64. The hardware used for porting
is a two-module system, consisting of a base compute module and a
CPU expansion module. SGI's NUMAFlex architecture can be an excellent
platform to test CPU affinity and NUMA-aware features in FreeBSD.

- Import the HEAD csup code which is the basis for the cvsmode work.

Just leave out a few includes to compile this on FreeBSD.