INT 31 - DOS32 v3.0+ - ALLOCATE MEMORY BLOCK                                    
	AX = EE42h
	EDX = size in bytes
Return: CF clear if successful
	    EAX = size in bytes
	    EDX -> memory block
	CF set on error
Note:	size is rounded off to the next 4KB boundary
SeeAlso: AX=EE40h,AX=EE41h