New flag for 'clipboard' option: "unnamed" which uses plus register

[Ivan Krasilnikov]

Hello,

I want yank and paste commands to use the system clipboard by default.
Vim has an option for this: clipboard=unnamed which makes yank and
paste work with the register '*' instead of the unnamed register. This
works great on Windows where '*' is the clipboard. However, on X11 the
clipboard is the '+' register, and so I find myself having to type "+y
and "+p instead of the shorter y and p when I want to use the
clipboard.

Attached is a patch which adds a new flag "unnamedplus" to the
'clipboard' option, which behaves exactly like the "unnamed" flag,
except that it uses the '+' register. Please, consider it for
inclusion in Vim. Thanks.

--
Ivan Krasilnikov