1 files changed, 1 insertions, 1 deletions
diff --git a/ruby.c b/ruby.c
index 5d544e7cad..bb7a9d0cda 100644
--- a/ruby.c
+++ b/ruby.c
@@ -775,7 +775,7 @@ proc_options(argc, argv)
 		    }
 		}
 		if (!*s) break;
-		if (!strchr("IdvwrK", *s))
+		if (!strchr("IdvwWrK", *s))
 		    rb_raise(rb_eRuntimeError, "illegal switch in RUBYOPT: -%c", *s);
 		s = moreswitches(s);
 	    }