compat/w32pthreads: use the condition variable API directly when targeting newer versions of Windows

Wrap the function calls in a similar fashion to how it's being done
with the critical section API.

Reviewed-by: Michael Niedermayer <michaelni@gmx.at>
Signed-off-by: James Almer <jamrial@gmail.com>
ffplay: dont leave swresampler in half initialized state

On init failure, let's just free it, so next time it will be recreated from
start.

Also fixes Coverity CID 1241515.

Reviewed-by: Michael Niedermayer <michaelni@gmx.at>
Signed-off-by: Marton Balint <cus@passwd.hu>