* Create a --version and --compatibility-version flags (?).

* Add --enable-debug flag to configure.

* Create xls2xml-config script.

* Add signal trap in main.c (do it plataform independent with autoconf)
  (example: delete xml_doc and close and umount all on KILL signal)

* Make xls2xml handle parameters using getopt_long.

* Dump the contents of `*SummaryInformation' streams.

* Identify test* macros that can be not compiled (because they serve as assert).

* Check at the begining of each record it's called when seen the apropiate substream type.

* Support compression (via libxml).

* Map CP152* codes to UTF8.