diff --git a/library/include/locale.h b/library/include/locale.h
index fe3bbd8..66e50fe 100644
--- a/library/include/locale.h
+++ b/library/include/locale.h
@@ -59,6 +59,10 @@ extern "C" {
 
 /****************************************************************************/
 
+typedef void *locale_t;
+
+/****************************************************************************/
+
 struct lconv
 {
 	char *	decimal_point;		/* Decimal point character (non-monetary). */
diff --git a/library/include/stdlib.h b/library/include/stdlib.h
index cda40f7..b1d48a8 100644
--- a/library/include/stdlib.h
+++ b/library/include/stdlib.h
@@ -447,6 +447,11 @@ extern lldiv_t lldiv(long long n,long long d);
 
 /****************************************************************************/
 
+extern int mbtowc(wchar_t *restrict pwc, const char *restrict s, size_t n);
+extern int wctomb(char *s, wchar_t wchar);
+
+/****************************************************************************/
+
 #endif /* __GNUC__ || (__STDC_VERSION__ && __STDC_VERSION__ >= 199901L) */
 
 /****************************************************************************/
diff --git a/library/include/wchar.h b/library/include/wchar.h
index eb04a94..dfa728f 100644
--- a/library/include/wchar.h
+++ b/library/include/wchar.h
@@ -59,6 +59,10 @@
 #include <time.h>
 #endif /* _TIME_H */
 
+#ifndef _LOCALE_H
+#include <locale.h>
+#endif /* _LOCALE_H */
+
 /****************************************************************************/
 
 #ifdef __cplusplus
@@ -81,9 +85,6 @@ typedef long mbstate_t;
 extern wint_t btowc(int c);
 extern int wctob(wint_t c);
 extern int mbsinit(const mbstate_t *ps);
-#if defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L)
-extern size_t mbrlen(const char *restrict s, size_t n, mbstate_t *restrict ps);
-#endif /* __STDC_VERSION__ && __STDC_VERSION__ >= 199901L */
 extern size_t wcrtomb(char *s, wchar_t wc, mbstate_t *ps);
 extern size_t mbsrtowcs(wchar_t *pwcs, const char **src, size_t n, mbstate_t *ps);
 extern size_t wcsrtombs(char *s, const wchar_t **src, size_t n, mbstate_t *ps);
@@ -178,14 +179,20 @@ extern size_t wcsftime(wchar_t *s, size_t maxsize, const wchar_t *format, const
 
 #if defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L)
 
+extern size_t mbrlen(const char *restrict s, size_t n, mbstate_t *restrict ps);
+extern size_t mbrtowc(wchar_t *restrict pwc, const char *restrict s, size_t n, mbstate_t *restrict ps);
+extern int mbsinit(const mbstate_t *ps);
+extern size_t mbsnrtowcs(wchar_t *restrict dst, const char **restrict src, size_t nmc, size_t len, mbstate_t *restrict ps);
+extern size_t mbsrtowcs(wchar_t *restrict dst, const char **restrict src, size_t len, mbstate_t *restrict ps);
+
+extern size_t wcrtomb(char *restrict s, wchar_t wc, mbstate_t *restrict ps);extern int wcscoll_l(const wchar_t *ws1, const wchar_t *ws2, locale_t loc);
+extern size_t wcscspn(const wchar_t *ws1, const wchar_t *ws2);
+extern size_t wcsnrtombs(char *restrict dst, const wchar_t **restrict src, size_t nwc, size_t len, mbstate_t *restrict ps);
+extern wchar_t * wcsrchr(const wchar_t *ws, wchar_t wc);
+extern size_t wcsrtombs(char *restrict dst, const wchar_t **restrict src, size_t len, mbstate_t *restrict ps);
 extern long long wcstoll(const wchar_t *str, wchar_t **ptr, int base);
 extern unsigned long long wcstoull(const wchar_t *str, wchar_t **ptr, int base);
 
-extern size_t mbrtowc_l(wchar_t *restrict pwc, const char *restrict s, size_t n, mbstate_t *restrict ps, locale_t loc);
-extern int wcscoll_l(const wchar_t *ws1, const wchar_t *ws2, locale_t loc);
-extern size_t wcscspn(const wchar_t *ws1, const wchar_t *ws2);
-extern wchar_t * wcsrchr(const wchar_t *ws, wchar_t wc);
-
 #endif /* __STDC_VERSION__ && __STDC_VERSION__ >= 199901L */
 
 /****************************************************************************/
diff --git a/library/stdlib_mbtowc.c b/library/stdlib_mbtowc.c
index 4835146..0d592a6 100644
--- a/library/stdlib_mbtowc.c
+++ b/library/stdlib_mbtowc.c
@@ -37,9 +37,13 @@
 
 /****************************************************************************/
 
+#if defined(defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L))
+
 int
-mbtowc(wchar_t *pwc, const char *s, size_t n)
+mbtowc(wchar_t *restrict pwc, const char *restrict s, size_t n)
 {
 	/* ZZZ unimplemented */
 	return(-1);
 }
+
+#endif