Add wchar.h and wctype.h compatibility shims using ucd-tools. This is applied to all platforms to provide consistent behaviour.

src/include/compat/wchar.h

+/* Compatibility shim for <wchar.h>
+ *
+ * Copyright (C) 2017 Reece H. Dunn
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see: <http://www.gnu.org/licenses/>.
+ */
+
+#ifdef _MSC_VER
+#if _MSC_VER >= 1900 // Visual C++ 14 (Visual Studio 2015) and above...
+#include <../ucrt/wchar.h>
+#else
+#include <../include/wchar.h>
+#endif
+#else
+#pragma GCC system_header // Silence "warning: #include_next is a GCC extension"
+#include_next <wchar.h>
+#endif
+
+#ifndef WCHAR_H_COMPAT_SHIM
+#define WCHAR_H_COMPAT_SHIM
+
+#include <ucd/ucd.h>
+
+#define towlower ucd_tolower
+#define towupper ucd_toupper
+
+#endif

src/include/compat/wctype.h

+/* Compatibility shim for <wctype.h>
+ *
+ * Copyright (C) 2017 Reece H. Dunn
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see: <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef WCTYPE_H_COMPAT_SHIM
+#define WCTYPE_H_COMPAT_SHIM
+
+#ifdef _MSC_VER
+#if _MSC_VER >= 1900 // Visual C++ 14 (Visual Studio 2015) and above...
+#include <../ucrt/wctype.h>
+#else
+#include <../include/wctype.h>
+#endif
+#else
+#pragma GCC system_header // Silence "warning: #include_next is a GCC extension"
+#include_next <wctype.h>
+#endif
+
+#include <ucd/ucd.h>
+
+#define iswalnum  ucd_isalnum
+#define iswalpha  ucd_isalpha
+#define iswblank  ucd_isblank
+#define iswcntrl  ucd_iscntrl
+#define iswdigit  ucd_isdigit
+#define iswgraph  ucd_isgraph
+#define iswlower  ucd_islower
+#define iswprint  ucd_isprint
+#define iswpunct  ucd_ispunct
+#define iswspace  ucd_isspace
+#define iswupper  ucd_isupper
+#define iswxdigit ucd_isxdigit
+
+#endif