FreeBSD_HEAD_arm64 - Build #4304 - Fixed

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FreeBSD_HEAD_arm64 - Build #4304 - Fixed:

Build information: https://jenkins.FreeBSD.org/job/FreeBSD_HEAD_arm64/4304/
Full change log: https://jenkins.FreeBSD.org/job/FreeBSD_HEAD_arm64/4304/changes
Full build log: https://jenkins.FreeBSD.org/job/FreeBSD_HEAD_arm64/4304/console

Change summaries:

309604 by loos:
Fix the armv6 build after r309553.

Sponsored by:	Rubicon Communications, LLC (Netgate)

309603 by avos:
rsu: fix printf format specifiers.

309602 by ngie:
Remove svn[lite]{bench,fsfs} if either MK_SVN == no or MK_SVNLITE == no

MFC after:	1 week

309599 by markj:
libdtrace: Don't use a read-only handle for enumerating pid probes.

Enumeration of return probes involves disassembling subroutines in the
target process, and ptrace(2) is currently used to read from the target
process. libproc could read from the backing file instead to avoid this
problem, but in the common case libdtrace will have a writeable handle
on the process anyway. In particular, a writeable handle is needed to list
USDT probes, and libdtrace will cache such a handle for processes that it
controls via dtrace -c and -p.

309598 by markj:
Bump the libproc library version.

309597 by markj:
libproc: Add support for some proc_attach() flags.

This change adds some handling for the equivalent of Solaris' PGRAB_*
flags. In particular, support for PGRAB_RDONLY is needed to avoid a
nasty deadlock: dtrace(1) may otherwise stop the master process for its
pseudo-terminal and end up blocking while writing to standard output.

309596 by markj:
libproc: Cache symbol tables for mapped objects upon access.

Extend the file handle cache entries to include symbol tables as well. An
index is used to implement binary search by symbol value. Lookups by
name are comparatively rare and are thus still implemented with a linear
search, but support for a binary search by name would be straightforward
to add if needed.

309595 by markj:
libproc: Match prefixes when looking up mapped object by name.

When looking up an object by name, allow prefix matches if no direct match
is found. This allows one to, for example, match libc entry probes with:

 # dtrace -n 'pid$target:libc.so::entry' -c ./foo

instead of requiring "libc.so.7" or a glob.

Also remove proc_obj2map() as it currently just duplicates the
functionality of proc_name2map(). It's supposed to take a Solaris
link-map ID as a paramter, but support for this isn't implemented and
isn't required to support DTrace's pid provider.

309594 by markj:
libproc: Cache ELF handles for loaded objects.

libproc previously created a new handle for each symbol lookup, which
gives rather egregious performance for DTrace's ustack() action. With
this change libproc will cache the libelf descriptor upon access, making
lookups much faster in the common case.

309593 by markj:
libproc: Improve .gnu_debuglink support.

As of r278658 libproc looks for debug files under /usr/lib/debug and will
use them if available. This change fleshes out that support a bit further:
- Check for a .gnu_debuglink section and use the file name specified
  there if one is present.
- Validate external debug files with the CRC in the .gnu_debuglink
  section so as to avoid using stale or corrupt debug files.
- Search for debug files in the directory containing the referencing
  object or in the .debug subdirectory, as GDB does.

309592 by markj:
libproc: Make proc_getpid() an accessor for struct proc_handle.

This allows librtld_db to fetch the PID from a handle without calling into
libproc. Together with r303531, this means that librtld_db no longer
references symbols from libproc.

309591 by markj:
Fix style bugs and remove trailing whitespace in libproc and librtld_db.

MFC after:	1 week