Ask the terminal whether the mode is already on (DECRQM) and put it back
that way on exit. Forcing it off broke pasting in shells that run fzf
from a line editor widget, which enable the mode only when the editor
starts. Terminals that do not answer fall back to disabling it.
- Startup queries go out in one write, cursor position last. Every
terminal answers DSR, so its reply bounds the wait: a paste reply
still missing by then means the terminal does not know the query.
- Bound the first read with select(2). Terminals that never answer
escape sequences, such as FreeBSD virtual terminals, blocked startup
until a key was pressed, and that keystroke was then discarded.
Fix#4887Fix#2860Fix#976
Junegunn Choi
dab626bd9e