ck-0.7.1 fails validate/ck_sequence test in 1-core VM

[bmwiedemann]

I tested that this PoC-patch avoids the trouble

+++ ck-0.7.1/regressions/ck_sequence/validate/ck_sequence.c
@@ -124,6 +124,7 @@ main(int argc, char *argv[])

    n_threads = atoi(argv[1]) - 1;
        if (n_threads <= 0) {
+               return 0;
                ck_error("ERROR: Number of threads must be greater than 0\n");
        }

This bug was found while working on reproducible builds for openSUSE.