MFC 306564: Expose kernel-only errno values if _WANT_KERNEL_ERRNO is defined.

The kernel uses a few negative errno values for internal conditions
such as requesting a system call restart. Normally these errno values
are not exposed to userland. However, kdump needs access to these
values as some of then can be present in a ktrace system call return
record. Previously kdump was defining _KERNEL to gain access to ehse
values, but was then having to manually declare 'errno' (and doing it
incorrectly). Now, kdump uses _WANT_KERNEL_ERRNO instead of _KERNEL
and uses the system-provided declaration of errno.

MFC 306563: Decode arguments to truncate and ftruncate.

In particular, decode the off_t argument as a 64-bit argument to fix
decoding for 32-bit processes.

MFC 306562: Handle 64-bit system call arguments (off_t, id_t).

In particular, 64-bit system call arguments use up two register_t
arguments for 32-bit processes. They must also be aligned on a 64-bit
boundary on 32-bit powerpc processes. This fixes the decoding of
lseek(), procctl(), and wait6() arguments for 32-bit processes (both
native and via freebsd32).

Note that the ktrace system call return record only returns a single
register, so the return value of lseek is always truncated to the low
32-bits for 32-bit processes.

MFC r302770:
Trace timeval parameters to the getitimer(2) and setitimer(2) syscalls.

MFC r300428:

Fix humanized decoding of struct stat with respect to .st_mtim

st_mtim was being incorrectly described as "stime=", not "mtime=". This was
introduced with the original feature commit (r176471).

PR: 209699

MFC r283430:

Teach kdump to understand both linux emulation.

MFC r277610 (by jillies):

Add futimens and utimensat system calls.

MFH (r277695): allow tracing dlfunc() / dlsym() events

Merge an applicable subset of r263234 from HEAD to stable/10:

Update most userspace consumers of capability.h to use capsicum.h instead.

auditdistd is not updated as I will make the change upstream and then do a
vendor import sometime in the next week or two.

Note that a significant fraction does not apply, as FreeBSD 10 doesn't
contain a Capsicumised ping, casperd, libcasper, etc. When these features
are merged, the capsicum.h change will need to be merged with them.

Sponsored by: Google, Inc.

MFC r278857:
kdump: sendfile(2) "flags" argument needs casting on 64-bit platforms.

Sponsored by: Nginx, Inc.

MFC r273048 by jhb:

Fix most of the warnings in kdump(1).

r276758:

Eliminate new clang warnings.

MFC 273053:
Decode the arguments passed to _umtx_op(). In particular, decode the
opcode.

MFC r269408, r269409:

shm_open()/shm_unlink() ktrace support.

MFC r263879:

Add `-S' to display syscall numbers in the output as well.

MFH (r277695): allow tracing dlfunc() / dlsym() events

Merge an applicable subset of r263234 from HEAD to stable/10:

Update most userspace consumers of capability.h to use capsicum.h instead.

auditdistd is not updated as I will make the change upstream and then do a
vendor import sometime in the next week or two.

Note that a significant fraction does not apply, as FreeBSD 10 doesn't
contain a Capsicumised ping, casperd, libcasper, etc. When these features
are merged, the capsicum.h change will need to be merged with them.

Sponsored by: Google, Inc.

MFC r278857:
kdump: sendfile(2) "flags" argument needs casting on 64-bit platforms.

Sponsored by: Nginx, Inc.

MFC r273048 by jhb:

Fix most of the warnings in kdump(1).

r276758:

Eliminate new clang warnings.

MFC 273053:
Decode the arguments passed to _umtx_op(). In particular, decode the
opcode.

MFC r269408, r269409:

shm_open()/shm_unlink() ktrace support.

MFC r263879:

Add `-S' to display syscall numbers in the output as well.