demangle.h license

[DJ Delorie]

> I think it would be appropriate and reasonable to change
> include/demangle.h to add the exception clause used in cplus-dem.c
> and cp-demangle.c.  I'm not sure what to do with the issue of GPL
> vs. LGPL, but given the presence of the exception clause I'm not
> sure that it matters too much.
> 
> DJ, any thoughts?  Should I go ahead and do this?

I agree it would be appropriate and reasonable, however, all license
changes for existing files must be approved by the FSF.  I don't
expect them to have a problem with it though.

FYI the .c license was changed as the demangler was at one point used
in libstdc++, which itself had to have the exception clause.