INT 21 - DOS 2+ - "SWITCHAR" - GET SWITCH CHARACTER
	AX = 3700h
Return: AL = status
	    00h successful
		DL = current switch character
	    FFh unsupported subfunction
Desc:	Determine the character which is used to introduce command switches.
	  This setting is ignored by MS-DOS commands in version 4.0 and higher,
	  but is honored by many third-party programs and by Novell DOS 7
	  external commands
BUG:	Novell DOS 7's COMMAND.COM (prior to Update 15) fails to honor the
	  SwitChar setting for internal commands even though COMMAND.COM
	  honors it in its own command tail (i.e. COMMAND /?); even in Update
	  15, internal commands fail to honor SwitChar for the /? help option
Notes:	documented in some OEM(Original Equipment Manufacturer) a company which purchases components that are resold as part of its own products under the company's own brand name, e.g. a Gateway 2000-branded monitor may actually be a Mag or NEC monitor. versions of some releases of DOS
	supported by OS/2 compatibility box
	always returns AL=00h/DL=2Fh for MS-DOS 5+ and DR DOS 3.41-6.0
	Novell DOS 7 COMMAND.COM indicates switch characters other than '/'
	  by changing the first backslash (and only the first one) in the
	  path it prints for PROMPT $p with a forward slash
SeeAlso: AX=3701h