diff --git a/libc/include/locale.h b/libc/include/locale.h
index aa6b474..6989851 100644
--- a/libc/include/locale.h
+++ b/libc/include/locale.h
@@ -29,6 +29,7 @@
 #define _LOCALE_H_
 
 #include <sys/cdefs.h>
+#include <xlocale.h>
 
 __BEGIN_DECLS
 
@@ -43,12 +44,29 @@
     LC_PAPER     = 7,
     LC_NAME      = 8,
     LC_ADDRESS   = 9,
-
     LC_TELEPHONE      = 10,
     LC_MEASUREMENT    = 11,
     LC_IDENTIFICATION = 12
 };
 
+#define LC_CTYPE_MASK          (1 << LC_CTYPE)
+#define LC_NUMERIC_MASK        (1 << LC_NUMERIC)
+#define LC_TIME_MASK           (1 << LC_TIME)
+#define LC_COLLATE_MASK        (1 << LC_COLLATE)
+#define LC_MONETARY_MASK       (1 << LC_MONETARY)
+#define LC_MESSAGES_MASK       (1 << LC_MESSAGES)
+#define LC_PAPER_MASK          (1 << LC_PAPER)
+#define LC_NAME_MASK           (1 << LC_NAME)
+#define LC_ADDRESS_MASK        (1 << LC_ADDRESS)
+#define LC_TELEPHONE_MASK      (1 << LC_TELEPHONE)
+#define LC_MEASUREMENT_MASK    (1 << LC_MEASUREMENT)
+#define LC_IDENTIFICATION_MASK (1 << LC_IDENTIFICATION)
+
+#define LC_ALL_MASK (LC_CTYPE_MASK | LC_NUMERIC_MASK | LC_TIME_MASK | LC_COLLATE_MASK | \
+                     LC_MONETARY_MASK | LC_MESSAGES_MASK | LC_PAPER_MASK | LC_NAME_MASK | \
+                     LC_ADDRESS_MASK | LC_TELEPHONE_MASK | LC_MEASUREMENT_MASK | \
+                     LC_IDENTIFICATION_MASK)
+
 struct lconv {
     char* decimal_point;
     char* thousands_sep;
@@ -77,7 +95,14 @@
 };
 
 struct lconv* localeconv(void);
-extern char* setlocale(int, const char*);
+
+locale_t duplocale(locale_t);
+void freelocale(locale_t);
+locale_t newlocale(int, const char*, locale_t);
+char* setlocale(int, const char*);
+locale_t uselocale(locale_t);
+
+#define LC_GLOBAL_LOCALE ((locale_t) -1L)
 
 __END_DECLS
 
diff --git a/libc/include/xlocale.h b/libc/include/xlocale.h
new file mode 100644
index 0000000..f7eb8f4
--- /dev/null
+++ b/libc/include/xlocale.h
@@ -0,0 +1,36 @@
+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef _XLOCALE_H_
+#define _XLOCALE_H_
+
+/* If we just use void* here, GCC exposes that in error messages. */
+struct __locale_t;
+typedef struct __locale_t* locale_t;
+
+#endif /* _XLOCALE_H_ */