diff --git a/libc/include/string.h b/libc/include/string.h
index 611c31a..f0bed10 100644
--- a/libc/include/string.h
+++ b/libc/include/string.h
@@ -58,8 +58,11 @@
 extern char*  strcpy(char* __restrict, const char* __restrict);
 extern char*  strcat(char* __restrict, const char* __restrict);
 
-extern int    strcasecmp(const char *, const char *) __purefunc;
-extern int    strncasecmp(const char *, const char *, size_t) __purefunc;
+int strcasecmp(const char*, const char*) __purefunc;
+int strcasecmp_l(const char*, const char*, locale_t) __purefunc;
+int strncasecmp(const char*, const char*, size_t) __purefunc;
+int strncasecmp_l(const char*, const char*, size_t, locale_t) __purefunc;
+
 extern char*  strdup(const char *);
 
 extern char*  strstr(const char *, const char *) __purefunc;
@@ -68,6 +71,7 @@
 extern char*  strtok_r(char* __restrict, const char* __restrict, char** __restrict);
 
 extern char* strerror(int);
+extern char* strerror_l(int, locale_t);
 #if defined(__USE_GNU)
 extern char* strerror_r(int, char*, size_t) __RENAME(__gnu_strerror_r);
 #else /* POSIX */
diff --git a/libc/include/strings.h b/libc/include/strings.h
index ae261cf..1253006 100644
--- a/libc/include/strings.h
+++ b/libc/include/strings.h
@@ -41,22 +41,23 @@
 
 #include <sys/types.h>
 #include <sys/cdefs.h>
+#include <xlocale.h>
 
 __BEGIN_DECLS
 #if defined(__BIONIC_FORTIFY)
-#define bcopy(b1, b2, len) \
-  (void)(__builtin___memmove_chk((b2), (b1), (len), __bos0(b2)))
-#define bzero(b, len) \
-  (void)(__builtin___memset_chk((b), '\0', (len), __bos0(b)))
+#define bcopy(b1, b2, len) (void)(__builtin___memmove_chk((b2), (b1), (len), __bos0(b2)))
+#define bzero(b, len) (void)(__builtin___memset_chk((b), '\0', (len), __bos0(b)))
 #else
 #define bcopy(b1, b2, len) (void)(__builtin_memmove((b2), (b1), (len)))
 #define bzero(b, len) (void)(__builtin_memset((b), '\0', (len)))
 #endif
 
+int ffs(int);
 
-int	 ffs(int);
-int	 strcasecmp(const char *, const char *);
-int	 strncasecmp(const char *, const char *, size_t);
+int strcasecmp(const char*, const char*) __purefunc;
+int strcasecmp_l(const char*, const char*, locale_t) __purefunc;
+int strncasecmp(const char*, const char*, size_t) __purefunc;
+int strncasecmp_l(const char*, const char*, size_t, locale_t) __purefunc;
 
 __END_DECLS
 
diff --git a/libc/include/wchar.h b/libc/include/wchar.h
index 10a78b8..9e279d3 100644
--- a/libc/include/wchar.h
+++ b/libc/include/wchar.h
@@ -34,6 +34,7 @@
 #include <stdarg.h>
 #include <stddef.h>
 #include <time.h>
+#include <xlocale.h>
 
 #include <machine/wchar_limits.h>
 
@@ -112,6 +113,7 @@
 extern int vwscanf(const wchar_t*, va_list);
 extern size_t            wcrtomb(char *, wchar_t, mbstate_t *);
 extern int               wcscasecmp(const wchar_t *, const wchar_t *);
+extern int               wcscasecmp_l(const wchar_t *, const wchar_t *, locale_t);
 extern wchar_t          *wcscat(wchar_t *, const wchar_t *);
 extern wchar_t          *wcschr(const wchar_t *, wchar_t);
 extern int               wcscmp(const wchar_t *, const wchar_t *);
@@ -121,6 +123,7 @@
 extern size_t            wcsftime(wchar_t *, size_t, const wchar_t *, const struct tm *) __LIBC_ABI_PUBLIC__;
 extern size_t            wcslen(const wchar_t *);
 extern int               wcsncasecmp(const wchar_t *, const wchar_t *, size_t);
+extern int               wcsncasecmp_l(const wchar_t *, const wchar_t *, size_t, locale_t);
 extern wchar_t          *wcsncat(wchar_t *, const wchar_t *, size_t);
 extern int               wcsncmp(const wchar_t *, const wchar_t *, size_t);
 extern wchar_t          *wcsncpy(wchar_t *, const wchar_t *, size_t);