screen: don't push the longer-line indicator ($) to the next row

If the last two columns of a row would be taken up by a double-width
character (and the line is longer than that), don't print it, because
it wouldn't leave any room for the $ character.

This fixes https://savannah.gnu.org/bugs/?50491.
Reported-by: David Lawrence Ramsey <pooka109@gmail.com>
1 file changed