[M3devel] build problems with libunicode

[Elmar Stellnberger]

> The only target system that does not support such a conversion on its own would be
> Xorg/Trestle. You would need to convert to utf-16 and then byte swap for little endian
> machines as the XChar2b is defined as a struct with the hi byte first.
> 

However the XChar2b of X11 can only handle 16bit code units with up to 65536 chars
so that a more simple direct conversion would be appropriate in this case. I guess we
could even skip utf-16 support and simply take libunicode as is by fixing its compilation
errors though utf-16 is is widely in use by Qt, Gtk, Java and C# and proper support for it
will improve interoperability.