[REMINDER libX11] XIM: Allow modifier releases in compose sequences (#26705)

[wettstein509 at solnet.ch]

> could you please add a line or two how to test the function ?
> what does not work (what keys to press) what works after the patch ?

If you put following in your .XCompose:

  <Shift_R> <o>  : odiaeresis
  <Shift_L> : BackSpace

you can enter ö by pressing and releasing the right Shift key, and then
pressing o, and you can create a backspace by pressing and releasing the
left Shift key.  Note that not all programs handle non-symbol keysyms
like BackSpace created from the compose mechanism, but emacs, for
example, does.

Regards,

Andreas