Non-Free SGML entity files

[stressware2@ruggedinbox.com]

The package sgml-data includes non-Free files in the
sgml/entities/sgml-iso-entities*/ directories and the
sgml/html/entities/ directory under the following licence:

  'Permission to copy in any form is granted for use with conforming
   SGML systems and applications as defined in ISO 8879, provided this
   notice is included in all copies.'

Unless 'conforming SGML systems and applications' is broadly defined
in ISO 8879, then redistribution is highly restricted (I cannot check
ISO 8879, because it seems there is no gratis copy).

Files under the same licence are also included in linuxdoc-tools in
the directories iso-entities/entities/ and entity-map/sdata/ (for
example ISOtech).

Furthermore, files in the directory
classpath/tools/resource/gnu/classpath/tools/gjdoc/dtd/ent/ in GCC are
based on these files.

The SGML entity files are needed to build documentation for several
projects.

It seems like it would be difficult to write the SGML entity files
much differently, so it is possible that they are not copyrightable.