INT 67 U - QEMM-386 v4.23+ - INSTALLATION CHECK
        AH = 3Fh
        CX = 5145h ("QE")
        DX = 4D4Dh ("MM")
Return: AH = 00h if installed
            ES:DI -> QEMM API entry point
Notes:  if no other program has hooked INT 67, an alternate installation
          check is to test for the string
          "QUARTERDECK EXPANDED MEMORY MANAGER 386" at offset 14h in the INT 67
          handler's segment; the word at offset 12h contains the offset in
          the handler's segment of the API entry point
        MICEMM (Micronics Expanded Memory Manager) versions 2.0C and 4D support
          the alternate QEMM installation check and entry point functions 00h,
          02h, and 03h; version 4D only provides the signature string if the
          commandline argument "DV" is provided
        386MAX v6.01 responds to this call, but DESQview 2.42 does not
          recognize the returned entry point as providing QEMM's capabilities
          because a) only functions 0Ch (different from QEMM 0Ch) and
                        1000h-1009h are supported,
                  b) status is returned as for EMS functions, not QEMM funcs
                  c) the protected-mode entry point returned by function 1000h
                        only supports functions 0Ch, 1004h, 1005h, and 100Ah
        the string check mentioned above is not supported by 386MAX
SeeAlso: AX=5BF0h,AX=FFA5h,INT 15/AX=11DEh,INT 21/AX=4402h"QEMM"