kill alloca in favor of ssp

include "ioconf.h" to get the 'void <driver>attach(int count);' prototype.

branches: 1.12.74;
Start detangling lock.h from intr.h. This is likely to cause short term
breakage, but the mess of dependencies has been regularly breaking the
build recently anyhow.

branches: 1.11.8; 1.11.14; 1.11.20;
Make a minimal adaption to the new kthread_create() signature
by renaming swdmover_proc to swdmover_lwp, and pass in
&swdmover_backend as an argument to be used by the kthread.
Reviewed by ad@.

Merge some of the less invasive changes from the vmlocking branch:

- kthread, callout, devsw API changes
- select()/poll() improvements
- miscellaneous MT safety improvements

branches: 1.9.30; 1.9.32;
merge ktrace-lwp.

branches: 1.8.4;
nuke trailing whitespace

branches: 1.7.8; 1.7.10;
Fix another used-before-initialized bug that gcc uncovered.

Add support for xor2-xor8 to swdmover.

Add a software implementation of the iSCSI CRC32C algorithm. This
serves as an example of how the immediate value can be used by a
dmover function.

branches: 1.4.2;
For functions with inputs and outputs, we currently require that the
buffer types be the same; don't rely on the middle-end to enforce this
for us.

Error out if we get an unexpected buffer type.

branches: 1.2.2; 1.2.4; 1.2.6;
Grr, fix typo in RCS ID tag.

dmover(9) -- an interface to hardware-assisted data movers. This allows
clients to use a hardware-assisted data mover to clear a region of memory,
fill a region of memory with a specific value, copy a region of memory,
and perform simple boolean operations such as XOR on multiple regions
of memory.

Included here is a software back-end which can serve as an example of
how to write a back-end (and also provides a fall-back in case hardware
for a given function is not available), as well as a dmoverio(4) pseudo-
device which provides access to dmover(9) to userland via a message
passing interface.

dmover(9) is still a work-in-progress -- a few minor changes to the
interface are expected.