The former was deprecated with C++14.
According to the C++11 and C++17 standards, both files are identical.
Signed-off-by: Rosen Penev <rosenp@gmail.com>
This optimization is useless because sane pthread_cond_signal()
implementations check the number of waiters and do not invoke a system
call if there are none.
The check IsSeekableCurrentSong() was added by commit
44b200240f in version 0.20.19, but it
caused a regression: by doing the branch only if the current song is
seekable, the player would restart the current song if it was not
seekable, and later the initial seek would fail; but we already know
it's not seekable, and so we should fail early.