Add a pre-built windows binary

[mkatzNU]

It might not be a bad idea to have a windows binary available for download for this like you have for the greaseweazle software.

Thank you.

[kaunomedis]

Yeah, it could be fine. I managed to compile it when removed macro in util.h

  #define err(retval, ...)  fprintf(stderr, "Undefined error: %d\n", errno);
  /*
  #define err(retval, ...) do { \
      fprintf(stderr, __VA_ARGS__); \
      fprintf(stderr, "Undefined error: %d\n", errno); \
      exit(retval); \
  } while(0)
  */