add uchar.h minimal from GNU libc

include/uchar.h

@@ -0,0 +1,56 @@
+/* Copyright (C) 2011-2016 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+/*
+ *      ISO C11 Standard: 7.28
+ *	Unicode utilities	<uchar.h>
+ */
+
+#ifndef _UCHAR_H
+#define _UCHAR_H	1
+
+#include <features.h>
+
+#define __need_size_t
+#include <stddef.h>
+#define __need_mbstate_t
+#include <wchar.h>
+
+#ifndef __mbstate_t_defined
+__BEGIN_NAMESPACE_C99
+/* Public type.  */
+typedef __mbstate_t mbstate_t;
+__END_NAMESPACE_C99
+# define __mbstate_t_defined 1
+#endif
+
+
+#if defined __GNUC__ && !defined __USE_ISOCXX11
+/* Define the 16-bit and 32-bit character types.  Use the information
+   provided by the compiler.  */
+# if !defined __CHAR16_TYPE__ || !defined __CHAR32_TYPE__
+#  if defined __STDC_VERSION__ && __STDC_VERSION__ < 201000L
+#   error "<uchar.h> requires ISO C11 mode"
+#  else
+#   error "definitions of __CHAR16_TYPE__ and/or __CHAR32_TYPE__ missing"
+#  endif
+# endif
+typedef __CHAR16_TYPE__ char16_t;
+typedef __CHAR32_TYPE__ char32_t;
+#endif
+
+#endif	/* uchar.h */