Vendor import of tcpdump 4.4.0.
MFV: tcpdump 4.4.0.

MFC after:	4 weeks
- Checking for spurious interrupts is only necessary when using INTx.
  Actually, this may be further optimized for controller variants
  supporting one-shot MSIs but I'm lacking the necessary hardware for
  testing.
- Add some missing synchronization of the statistics and status DMA
  maps.

MFC after:	1 week
Convert Makefile to have only one file for each line, while I'm there, sort
SRCS to ease future upgrades.
Diff reduction against tcpdump revision 949a22064d3534eddeb8aa2b9c36a50e45fe16fa.
Add macros which allow one to define SDT probes with six or seven arguments;
they are needed when porting some of the Solaris providers (ip, iscsi, and
tcp in particular).

dtrace_probe() only takes five arguments from the probe site, so we need to
add the appropriate cast to allow for more than five arguments. The extra
arguments are later copied out of dtrace_probe()'s stack frame by
dtrace_getarg() (or the provider-specific getarg method) as needed.

MFC after:	1 week
If the -r option is given we cannot enter capability mode.
The option tells kdump to convert numeric UIDs and GIDs into user and
group names plus to convert times and dates into locallized versions.
This all needs opening various files at various occasions.
Remove unused files.
Revert files with no local changes to their vendor state to ease future
upgrading.
 - Convert the bufobj lock to rwlock.
 - Use a shared bufobj lock in getblk() and inmem().
 - Convert softdep's lk to rwlock to match the bufobj lock.
 - Move INFREECNT to b_flags and protect it with the buf lock.
 - Remove unnecessary locking around bremfree() and BKGRDINPROG.

Sponsored by:	EMC / Isilon Storage Division
Discussed with:	mckusick, kib, mdf
xpt_create_path() requires mfi_io_lock to be held, so do it.

mfi(4) doesn't panic on host startup now.

MFC this if svn 249468-242726 is shoveled back to stable/9

Obtained from:	Yahoo! Inc.
Allow building with clang (which is being really stupid here...).
Different approach to making all compilers happy.
Apply the ad* => ada* IDE device name transition to the Xen block
front driver.

Submitted by:	Bei Guan <gbtju85@gmail.com>
Reviewed by:	gibbs
MFC after:	1 week
Make netif_free() safe to call on a partially initialized softc.

Sponsored by:	Spectra Logic Corporation
MFC after:	1 week