diff --git a/src/chars.c b/src/chars.c
index 3b7bf6c6b7836003e32aecf9092ad7fc1dd0e865..2c8b12b24e888541155e7760a14fce19eff9c5d3 100644
--- a/src/chars.c
+++ b/src/chars.c
@@ -840,7 +840,7 @@ bool has_blank_mbchars(const char *s)
 #endif
 	return has_blank_chars(s);
 }
-#endif
+#endif /* ENABLE_NANORC */
 
 /* This function is equivalent to strchr() for multibyte strings. */
 char *mbstrchr(const char *s, char *c)