diff -Naur bc-1.07.1/bc/scan.l bc-1.07.1-new/bc/scan.l
--- bc-1.07.1/bc/scan.l	2017-04-07 22:20:02.000000000 +0000
+++ bc-1.07.1-new/bc/scan.l	2021-08-14 12:12:33.860991777 +0000
@@ -170,6 +170,10 @@
       if (rl_len != 1)
 	add_history (rl_line); 
       rl_line[rl_len-1] = '\n';
+      /* readline doesn't echo empty lines without a prompt,
+         so do so here. */
+      if (rl_len == 1)
+        putchar ('\n');
       fflush (stdout);
     }