INT 10 - VESA XGA BIOS Extensions - GET XGA ENVIRONMENT INFORMATION

	AX = 4E00h
	ES:DI -> 256-byte buffer for XGA information (see #00069)
Return: AL = 4Eh if function supported
	    AH = status
		00h successful
		else error code
Desc:	determine whether VESA XGA extensions are present and the capabilities
	  supported by the display adapter
SeeAlso: AX=4E01h,AX=4E02h,AX=4F00h
Index:	installation check;VESA XGA