Swap Support #2
	-- 2001/04/01 ska

This style of swapping is incompatible with XMS-Only swapping!

This swapping is derived from KSSF (see k-swap.txt), but instead of
let the user decide what shell to execute, this swap faker uses a fixed
filename.

Useage:	VSPAWN [{ argument }]

VSpawn creates the filename of the shell to execute itself by replacing
its own file extension by .SWP. All the arguments are passed to the
invoked shell unchanged.

Most useful installation:

Make COMMAND.COM and TOOLS\VPSAWN.COM by running BUILD.BAT.

Rename COMMAND.COM into COMMAND.SWP.

Move TOOLS\VPSAWN.COM to COMMAND.COM.

Run COMMAND.COM.
VSpawn automatically invokes COMMAND.SWP;
COMMAND.SWP determines that it has been invoked using the VSpawn
feature and will maintain %COMSPEC%==*.COM, but will use *.SWP as
resource file.

Because the COMSPEC variable contains the *.COM filename, which is the
VSpawn wrapper, all subsequent invocations of a secondary shell will
use the VSpawn wrapper as well.

===

If FreeCOM detects the VSpawn feature beeing used, it defaults to
swap when executing external commands.
This can be suppressed by invoking external commands by:
CALL /N prg
or passing the option /SWAP to FreeCOM.

If auto-swap is not active, /SWAP enables it.