Try to fix a race that can occur when CTRL+C is pressed. The CTRL+C is received by the solver which kills it but we didn't wake up the thread waiting on a response when running in persistent mode.
Try to fix a race that can occur when CTRL+C is pressed. The CTRL+C
is received by the solver which kills it but we didn't wake up the
thread waiting on a response when running in persistent mode.

symbooglix/symbooglix,symbooglix/symbooglix,symbooglix/symbooglix