Clipboard functions for x11new about pdcurses

[wmcbrine]

A question : I see you're still making improvements to the "original" fork()-using x11 platform. Do you expect that to fade away now that we've got x11new to play with? Is there still a use for the "original" platform?

x11new isn't quite ready to take over yet. For one (more) thing, the problem you described in 9496141 is still present. (I found a simple fix that made the composed input work -- except that it then came in doubled.) But even once I'm satisfied with it, I'll want at least one broad release with both ports, to get x11new tested more widely before fully committing to it.

[wmcbrine]

So... it's pretty much ready now. I fixed the composed input ( 985e843 ), I redid the clipboard functions for x11new (without threads), and I wrote a "universal" (all platforms) cut-and-paste mechanism, on the curses side, to handle mouse select and paste, as well as keyboard (shift-ctrl-c and shift-ctrl-v). There are still some improvements to make, but it's at the level where the old x11 was before (plus keyboard paste, plus sdl2 has cut-and-paste support for the first time).