Correct way to assign value to mpz_t is to use openmp's funcion-like macro,
because it's horrible one-element array.
https://bugs.gentoo.org/920324
--- a/top/eratosthenes/soe_util.c
+++ b/top/eratosthenes/soe_util.c
@@ -131,7 +131,7 @@
 			sdata->pbound = sieve_p[num_sp - 1];
 			sdata->pboundi = num_sp;
 		}
-		sdata->offset = offset;
+		mpz_set(*(sdata->offset), offset);
 		mpz_clear(tmpz);
 		sdata->sieve_range = 1;
 	}