INT 21 - Q87, Q387 - ENABLE EMULATOR

	AX = 4321h
	BX = 0001h
	EAX = 87654321h (entire EAX value is required, not just AX)
Desc:	enable the emulator by setting the CPU MSW's EM bit and updating
	  the BIOS equipment list
Note:	this function is available only in virtual-86 mode in older versions;
	  newer versions also provide it in MS Windows 16- and 32-bit protected
	  mode
SeeAlso: AX=4321h/BX=0000h,AX=4321h/BX=0002h