INT 31 P - DPMI 0.9+ - ALLOCATE LDT DESCRIPTORS
        AX = 0000h
        CX = number of descriptors to allocate
Return: CF clear if successful
            AX = base selector
        CF set on error
            AX = error code (DPMI 1.0+)
                0000h-7FFFh DOS error passed through by DPMI
                8001h unsupported function
                8002h object in wrong state for function
                8003h system integrity would be endangered
                8004h deadlock detected
                8005h pending serialization request cancelled
                8010h out of DPMI internal resources
                8011h descriptor unavailable
                8012h linear memory unavailable
                8013h physical memory unavailable
                8014h backing store unavailable
                8015h callback unavailable
                8016h handle unavailable
                8017h maximum lock count exceeded
                8018h shared memory already serialized exclusively by another
                8019h shared memory already serialized shared by another client
                8021h invalid value for numeric or flag parameter
                8022h invalid segment selector
                8023h invalid handle
                8024h invalid callback
                8025h invalid linear address
                8026h request not supported by hardware
Notes:  DPMI is the DOS Protected-Mode Interface
        the base and limit of the returned descriptors will be 0, and the type
          will be "data"
        add the value returned by INT 31/AX=0003h to move to subsequent
          descriptors if multiple descriptors were allocated
        not supported by MS Windows 3.0 in Standard mode
SeeAlso: AX=000Dh,INT 21/AX=3501h