Somehow I've missed release of Emacs 21.2. I've noticed new version only now while it have been out for one mounth. So what interesting is in NEWS file?
Emacs now supports ICCCM Extended Segments in X selections.
Some versions of X, notably XFree86, use Extended Segments to encode in X selections characters that belong to character sets which are not part of the list of standard charsets supported by the ICCCM spec. Examples of such non-standard character sets include ISO 8859-14, ISO 8859-15, KOI8-R, and BIG5. To paste selections with such characters into Emacs, use the new coding system compound-text-with-extensions as the value of selection-coding-system.
Yes!!! Finally cut (from any X11 app) & paste (to Emacs) with cyrillic works again! I recall it was broken since I've started using XFree86 4.0.0 and I even somehow managed to get used to it.