Exec/signal handler: print message signal-safe

void interrupt_handler(int) {

    // Stop the framework if it is loaded

    if(apx_ready) {

        LOG(STATUS) << "Interrupted! Finishing up active events...";

        // Use signal-safe way of writing to STDERR

        const char str[] = "\nReceived interruption signal, finishing simulation...\n";

        if(write(STDERR_FILENO, str, sizeof(str) - 1)) {

        };

        apx->terminate();

    }

}