maint: prepare forthcoming changes

* src/gram.c (rule_rhs_print): Do not print new line anymore.
(rule_print): Make it static.
* src/closure.c, src/derives.c, src/gram.c: Adjust.

src/derives.c

@@ -52,6 +52,7 @@ print_derives (void)
         {
           fprintf (stderr, "\t\t%3d ", (*rp)->user_number);
           rule_rhs_print (*rp, stderr);
+          fprintf (stderr, "\n");
         }
     }