step: handle ctrl+D.

src/mumble.c

@@ -11,7 +11,9 @@ int main(int argc, char** argv)
         fputs("mumble> ", stdout);
         void* catcher = fgets(input, 2048, stdin);
         if (catcher == NULL) {
+            // ^ catches Ctrl+D
             loop = 0;
+            puts("");
         } else {
             printf("You said: %s", input);
         }