-/* Get mbstate_t, mbrtowc(), mbsinit(), wcwidth(). */
+/* Get mbstate_t, mbrtowc(), mbsinit(). */
+#if HAVE_WCHAR_H
+/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
+ <wchar.h>.
+ BSD/OS 4.1 has a bug: <stdio.h> and <time.h> must be included before
+ <wchar.h>. */
+# include <stdio.h>
+# include <time.h>
+# include <wchar.h>
+#endif
+
+/* Get wcwidth(). */