Support for ICCCM Extended Segments in X selections

[Eli Zaretskii]

I installed today changes that should add support for Extended
Segements in X selections.  Extended Segements are those special
leading control sequences that designate character sets beyond the
list of standard charsets that is given in the ICCCM spec; one notable
example is ISO 8859-15.  Those control sequences begin with "ESC % /",
and users of latest versions of XFree86 reported their sightings in X
selections pasted into Emacs.

Could people who use those versions of XFree86 and set their locales
to ISO 8859-15 please test the new feature and see if it performs as
expected?

A similar feature is available on the RC if you set your
selection-coding-system to compound-text-with-extensions.

In the CVS head version, you can have the previous behavior of X
selection encoding by setting selection-coding-system to
compound-text-no-extensions; the new behavior is on by default in CVS
head.

I'd like to thank Handa-san for his guidance while I worked on this.

Enjoy.