INT 62 u - FGDRIVER v4.02 - "FG_UNPACK" - EXPAND MODE-SPECIFIC BITMAP
	AX = 00CBh
	ES:BX -> variable pointer record (see #03509)
	CX = size of source bitmap in bytes
Return: result buffer filled
Note:	the FGDRIVER functions are rearranged with each major release, but
	  their parameters do not change (see #03474)
SeeAlso: AX=0083h


Format of FGDRIVER UNPACK variable pointer record:
Offset	Size	Description	(Table 03509)
 00h	WORD	segment of source bitmap
 02h	WORD	offset of source bitmap
 04h	WORD	segment of buffer for resulting bitmap
 06h	WORD	offset of buffer for resulting bitmap