INT 31 P - DPMI 0.9+ - CREATE ALIAS DESCRIPTOR
        AX = 000Ah
        BX = selector
Return: CF clear if successful
            AX = new data selector
        CF set on error
            AX = error code (DPMI 1.0+) (8011h,8022h) (see AX=0000h)
Notes:  fails if selector in BX is not a code segment or is invalid
        use INT 31/AX=0001h to free new selector
        future changes to the original selector will not be reflected in the
          returned alias selector
        not supported by MS Windows 3.0 in Standard mode