Using the clipboard in development version of Emacs

[Dan Davison]

I'm using Emacs compiled from recent source, under Linux. There have
been changes to the way Emacs interacts with the clipboard: e.g., if
text is selected in an X application, `yank' no longer pastes it into an
Emacs buffer; similarly `kill-region' no longer stores the text in a way
that middle-click will paste it into an X application.

Can anyone tell me how to get the behaviour I'm looking for (implied
above), or point me to the relevant discussion?

Thanks,

Dan