INT 21 - DOS 2+ - "SWITCHAR" - SET SWITCH CHARACTER
	AX = 3701h
	DL = new switch character
Return: AL = status
	    00h successful
	    FFh unsupported subfunction
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; DOS 2.x had
	  a SWITCHAR=c setting in CONFIG.SYS
	supported by OS/2 compatibility box and Novell DOS 7
	ignored by MS-DOS 5+ and DR DOS 3.41-6.0; DR DOS 6.0 and Novell DOS 7
	  leave AX unchanged
SeeAlso: AX=3700h