diff --git a/magnets.c b/magnets.c
index 815f016..5437c61 100644
--- a/magnets.c
+++ b/magnets.c
@@ -2562,7 +2562,7 @@ int main(int argc, const char *argv[])
         goto done;
     }
     s = new_game(NULL, p, desc);
-    printf("%s:%s (seed %ld)\n", id, desc, seed);
+    printf("%s:%s (seed %ld)\n", id, desc, (long)seed);
     if (aux) {
         /* We just generated this ourself. */
         if (verbose || print) {
diff --git a/signpost.c b/signpost.c
index e89a7c6..5650b2b 100644
--- a/signpost.c
+++ b/signpost.c
@@ -2393,7 +2393,7 @@ int main(int argc, const char *argv[])
         }
     }
 
-    sprintf(newseed, "%lu", time(NULL));
+    sprintf(newseed, "%lu", (unsigned long) time(NULL));
     seedstr = dupstr(newseed);
 
     if (id || !stdin_desc) {