Contents of the "qdos" subdirectory for UnZip 5.4 and later:

  Contents      this file
  IZREADME.SMS  release notes from Jonathan Hudson (author of port)
  Makefile      makefile for xtc68 cross-compiler on Linux (native QDOS exes)
  callstub.c    user interface stub for SMS/QDOS specific SFX archives
  config.S      assembler routine for ...?
  crc68.s       68000 version of CRC code
  izqdos.h      SMS/QDOS-specific header file
  makesfx.c     source for MakeSFX utility (simple concatenation does not work)
  qdos.c        SMS/QDOS-specific functions

Notes:

  "Makefile" is for the xtc68 cross compiler on Linux, but conversion to a
  native c68 makefile should be trivial.  To build a Linux (or other Unix)
  UnZip that understands QDOS extra fields, add "-DQLZIP" to the LOCAL_UNZIP
  environment variable and compile with the normal Unix makefile (for example,
  linux_asm target).  The "QLZIP" flag enables the Qdos "cross-UnZip" support
  in unix/unix.c.