After the latest commits, the fl2k tools do not exit on first SIGINT
It hangs after the first and then exits on the second.
[parker@stealth ~]$ fl2k_test -s 157e6 Allocating 6 zero-copy buffers libusb: error [op_dev_mem_alloc] alloc dev mem failed errno 12 Failed to allocate zero-copy buffer for transfer 4 Falling back to buffers in userspace Requested sample rate 157000000 not possible, using 157142851.000000, error is 142851.000000 Reporting PPM error measurement every 10 seconds... Press ^C after a few minutes. real sample rate: 157153750 current PPM: 69 cumulative PPM: 69 real sample rate: 157153688 current PPM: 69 cumulative PPM: 69 real sample rate: 157153733 current PPM: 69 cumulative PPM: 69 real sample rate: 157151996 current PPM: 58 cumulative PPM: 66 ^CSignal caught, exiting! User cancel, exiting... ^CSignal caught, exiting!