bug#13041: 24.2; diacritic-fold-search

[martin rudalics]

> Emacs contains ucs-normailze package which provides various
> normalization functions.  For instance,
>
> (require 'ucs-normalize)
> (ucs-normalize-NFKD-string "Äffin") => "Äffin"
>
> Isn't it usable?

Actually, the function should do what we need.  But I have no idea how
to integrate it into a searching algorithm.  And when sorting, it seems
expensive for comparing buffer substrings.  Also, the use of a temporary
buffer for normalizing every single string makes its weight quite heavy.

In any case, I would probably steal the entire decomposition property
handling part from it.  So thanks a lot for this hint.

martin