Re: isearch multiple buffers

[Richard Stallman]

    X10  (window-system-version mentions it, is it still supported?)

I think all code specific to X10 was all deleted ages ago.
There are a few conditionals that test HAVE_X11, but they really
use it to test whether X is present at all.

There are still conditionals for X11R3 (testing HAVE_X11R4).  That
must be long obsolete.  We can delete them if that would save us any
trouble.

Your list of platforms to propose to delete seems like a good start.
Please collect others' suggestions, then post the final list in a few
days.