diff --git a/include/cwchar b/include/cwchar
index 797a1777..ef4806db 100644
--- a/include/cwchar
+++ b/include/cwchar
@@ -106,9 +106,6 @@ size_t wcsrtombs(char* restrict dst, const wchar_t** restrict src, size_t len,
 #include <__config>
 #include <cwctype>
 #include <wchar.h>
-#if defined(_LIBCPP_MSVCRT) || defined(__MINGW32__)
-#include <support/win32/support.h> // pull in *swprintf defines
-#endif // _LIBCPP_MSVCRT
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #pragma GCC system_header
@@ -161,16 +158,13 @@ using ::wcscoll;
 using ::wcsncmp;
 using ::wcsxfrm;
 
-#if defined(_WCHAR_H_CPLUSPLUS_98_CONFORMANCE_)
-
+#ifdef _LIBCPP_WCHAR_H_HAS_CONST_OVERLOADS
 using ::wcschr;
 using ::wcspbrk;
 using ::wcsrchr;
 using ::wcsstr;
 using ::wmemchr;
-
 #else
-
 inline _LIBCPP_INLINE_VISIBILITY const wchar_t* wcschr(const wchar_t* __s, wchar_t __c) {return ::wcschr(__s, __c);}
 inline _LIBCPP_INLINE_VISIBILITY       wchar_t* wcschr(      wchar_t* __s, wchar_t __c) {return ::wcschr(__s, __c);}
 
@@ -185,7 +179,6 @@ inline _LIBCPP_INLINE_VISIBILITY       wchar_t* wcsstr(      wchar_t* __s1, cons
 
 inline _LIBCPP_INLINE_VISIBILITY const wchar_t* wmemchr(const wchar_t* __s, wchar_t __c, size_t __n) {return ::wmemchr(__s, __c, __n);}
 inline _LIBCPP_INLINE_VISIBILITY       wchar_t* wmemchr(      wchar_t* __s, wchar_t __c, size_t __n) {return ::wmemchr(__s, __c, __n);}
-
 #endif
 
 using ::wcscspn;
diff --git a/include/wchar.h b/include/wchar.h
new file mode 100644
index 00000000..da34f735
--- /dev/null
+++ b/include/wchar.h
@@ -0,0 +1,136 @@
+// -*- C++ -*-
+//===--------------------------- wchar.h ----------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#if defined(__need_wint_t) || defined(__need_mbstate_t)
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#include_next <wchar.h>
+
+#elif !defined(_LIBCPP_WCHAR_H)
+#define _LIBCPP_WCHAR_H
+
+/*
+    wchar.h synopsis
+
+Macros:
+
+    NULL
+    WCHAR_MAX
+    WCHAR_MIN
+    WEOF
+
+Types:
+
+    mbstate_t
+    size_t
+    tm
+    wint_t
+
+int fwprintf(FILE* restrict stream, const wchar_t* restrict format, ...);
+int fwscanf(FILE* restrict stream, const wchar_t* restrict format, ...);
+int swprintf(wchar_t* restrict s, size_t n, const wchar_t* restrict format, ...);
+int swscanf(const wchar_t* restrict s, const wchar_t* restrict format, ...);
+int vfwprintf(FILE* restrict stream, const wchar_t* restrict format, va_list arg);
+int vfwscanf(FILE* restrict stream, const wchar_t* restrict format, va_list arg);  // C99
+int vswprintf(wchar_t* restrict s, size_t n, const wchar_t* restrict format, va_list arg);
+int vswscanf(const wchar_t* restrict s, const wchar_t* restrict format, va_list arg);  // C99
+int vwprintf(const wchar_t* restrict format, va_list arg);
+int vwscanf(const wchar_t* restrict format, va_list arg);  // C99
+int wprintf(const wchar_t* restrict format, ...);
+int wscanf(const wchar_t* restrict format, ...);
+wint_t fgetwc(FILE* stream);
+wchar_t* fgetws(wchar_t* restrict s, int n, FILE* restrict stream);
+wint_t fputwc(wchar_t c, FILE* stream);
+int fputws(const wchar_t* restrict s, FILE* restrict stream);
+int fwide(FILE* stream, int mode);
+wint_t getwc(FILE* stream);
+wint_t getwchar();
+wint_t putwc(wchar_t c, FILE* stream);
+wint_t putwchar(wchar_t c);
+wint_t ungetwc(wint_t c, FILE* stream);
+double wcstod(const wchar_t* restrict nptr, wchar_t** restrict endptr);
+float wcstof(const wchar_t* restrict nptr, wchar_t** restrict endptr);         // C99
+long double wcstold(const wchar_t* restrict nptr, wchar_t** restrict endptr);  // C99
+long wcstol(const wchar_t* restrict nptr, wchar_t** restrict endptr, int base);
+long long wcstoll(const wchar_t* restrict nptr, wchar_t** restrict endptr, int base);  // C99
+unsigned long wcstoul(const wchar_t* restrict nptr, wchar_t** restrict endptr, int base);
+unsigned long long wcstoull(const wchar_t* restrict nptr, wchar_t** restrict endptr, int base);  // C99
+wchar_t* wcscpy(wchar_t* restrict s1, const wchar_t* restrict s2);
+wchar_t* wcsncpy(wchar_t* restrict s1, const wchar_t* restrict s2, size_t n);
+wchar_t* wcscat(wchar_t* restrict s1, const wchar_t* restrict s2);
+wchar_t* wcsncat(wchar_t* restrict s1, const wchar_t* restrict s2, size_t n);
+int wcscmp(const wchar_t* s1, const wchar_t* s2);
+int wcscoll(const wchar_t* s1, const wchar_t* s2);
+int wcsncmp(const wchar_t* s1, const wchar_t* s2, size_t n);
+size_t wcsxfrm(wchar_t* restrict s1, const wchar_t* restrict s2, size_t n);
+const wchar_t* wcschr(const wchar_t* s, wchar_t c);
+      wchar_t* wcschr(      wchar_t* s, wchar_t c);
+size_t wcscspn(const wchar_t* s1, const wchar_t* s2);
+size_t wcslen(const wchar_t* s);
+const wchar_t* wcspbrk(const wchar_t* s1, const wchar_t* s2);
+      wchar_t* wcspbrk(      wchar_t* s1, const wchar_t* s2);
+const wchar_t* wcsrchr(const wchar_t* s, wchar_t c);
+      wchar_t* wcsrchr(      wchar_t* s, wchar_t c);
+size_t wcsspn(const wchar_t* s1, const wchar_t* s2);
+const wchar_t* wcsstr(const wchar_t* s1, const wchar_t* s2);
+      wchar_t* wcsstr(      wchar_t* s1, const wchar_t* s2);
+wchar_t* wcstok(wchar_t* restrict s1, const wchar_t* restrict s2, wchar_t** restrict ptr);
+const wchar_t* wmemchr(const wchar_t* s, wchar_t c, size_t n);
+      wchar_t* wmemchr(      wchar_t* s, wchar_t c, size_t n);
+int wmemcmp(wchar_t* restrict s1, const wchar_t* restrict s2, size_t n);
+wchar_t* wmemcpy(wchar_t* restrict s1, const wchar_t* restrict s2, size_t n);
+wchar_t* wmemmove(wchar_t* s1, const wchar_t* s2, size_t n);
+wchar_t* wmemset(wchar_t* s, wchar_t c, size_t n);
+size_t wcsftime(wchar_t* restrict s, size_t maxsize, const wchar_t* restrict format,
+                const tm* restrict timeptr);
+wint_t btowc(int c);
+int wctob(wint_t c);
+int mbsinit(const mbstate_t* ps);
+size_t mbrlen(const char* restrict s, size_t n, mbstate_t* restrict ps);
+size_t mbrtowc(wchar_t* restrict pwc, const char* restrict s, size_t n, mbstate_t* restrict ps);
+size_t wcrtomb(char* restrict s, wchar_t wc, mbstate_t* restrict ps);
+size_t mbsrtowcs(wchar_t* restrict dst, const char** restrict src, size_t len,
+                 mbstate_t* restrict ps);
+size_t wcsrtombs(char* restrict dst, const wchar_t** restrict src, size_t len,
+                 mbstate_t* restrict ps);
+
+*/
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#ifdef __cplusplus
+#define __CORRECT_ISO_CPP_WCHAR_H_PROTO
+#endif
+
+#include_next <wchar.h>
+
+// Let <cwchar> know if we have const-correct overloads for wcschr and friends.
+#if defined(_WCHAR_H_CPLUSPLUS_98_CONFORMANCE_)
+#  define _LIBCPP_WCHAR_H_HAS_CONST_OVERLOADS 1
+#elif defined(__GLIBC_PREREQ)
+#  if __GLIBC_PREREQ(2, 10)
+#    define _LIBCPP_WCHAR_H_HAS_CONST_OVERLOADS 1
+#  endif
+#endif
+
+#if defined(__cplusplus) && (defined(_LIBCPP_MSVCRT) || defined(__MINGW32__))
+extern "C++" {
+#include <support/win32/support.h> // pull in *swprintf defines
+}  // extern "C++"
+#endif  // __cplusplus && _LIBCPP_MSVCRT
+
+#endif  // _LIBCPP_WCHAR_H
diff --git a/test/std/depr/depr.c.headers/wchar_h.pass.cpp b/test/std/depr/depr.c.headers/wchar_h.pass.cpp
index 031fd1f4..3ff13184 100644
--- a/test/std/depr/depr.c.headers/wchar_h.pass.cpp
+++ b/test/std/depr/depr.c.headers/wchar_h.pass.cpp
@@ -28,13 +28,9 @@
 #error WEOF not defined
 #endif
 
-#if defined(__clang__)
-#pragma clang diagnostic ignored "-Wmissing-braces"
-#endif
-
 int main()
 {
-    mbstate_t mb = {};
+    mbstate_t mb = {0};
     size_t s = 0;
     tm *tm = 0;
     wint_t w = 0;
@@ -54,19 +50,13 @@ int main()
     static_assert((std::is_same<decltype(vfwscanf(fp, L"", va)), int>::value), "");
     static_assert((std::is_same<decltype(vswprintf(ws, s, L"", va)), int>::value), "");
     static_assert((std::is_same<decltype(vswscanf(L"", L"", va)), int>::value), "");
-    static_assert((std::is_same<decltype(vwprintf(L"", va)), int>::value), "");
-    static_assert((std::is_same<decltype(vwscanf(L"", va)), int>::value), "");
-    static_assert((std::is_same<decltype(wprintf(L"")), int>::value), "");
-    static_assert((std::is_same<decltype(wscanf(L"")), int>::value), "");
     static_assert((std::is_same<decltype(fgetwc(fp)), wint_t>::value), "");
     static_assert((std::is_same<decltype(fgetws(ws, 0, fp)), wchar_t*>::value), "");
     static_assert((std::is_same<decltype(fputwc(L' ', fp)), wint_t>::value), "");
     static_assert((std::is_same<decltype(fputws(L"", fp)), int>::value), "");
     static_assert((std::is_same<decltype(fwide(fp, 0)), int>::value), "");
     static_assert((std::is_same<decltype(getwc(fp)), wint_t>::value), "");
-    static_assert((std::is_same<decltype(getwchar()), wint_t>::value), "");
     static_assert((std::is_same<decltype(putwc(L' ', fp)), wint_t>::value), "");
-    static_assert((std::is_same<decltype(putwchar(L' ')), wint_t>::value), "");
     static_assert((std::is_same<decltype(ungetwc(L' ', fp)), wint_t>::value), "");
     static_assert((std::is_same<decltype(wcstod(L"", (wchar_t**)0)), double>::value), "");
     static_assert((std::is_same<decltype(wcstof(L"", (wchar_t**)0)), float>::value), "");
@@ -83,14 +73,19 @@ int main()
     static_assert((std::is_same<decltype(wcscoll(L"", L"")), int>::value), "");
     static_assert((std::is_same<decltype(wcsncmp(L"", L"", s)), int>::value), "");
     static_assert((std::is_same<decltype(wcsxfrm(ws, L"", s)), size_t>::value), "");
+    static_assert((std::is_same<decltype(wcschr((const wchar_t*)0, L' ')), const wchar_t*>::value), "");
     static_assert((std::is_same<decltype(wcschr((wchar_t*)0, L' ')), wchar_t*>::value), "");
     static_assert((std::is_same<decltype(wcscspn(L"", L"")), size_t>::value), "");
     static_assert((std::is_same<decltype(wcslen(L"")), size_t>::value), "");
+    static_assert((std::is_same<decltype(wcspbrk((const wchar_t*)0, L"")), const wchar_t*>::value), "");
     static_assert((std::is_same<decltype(wcspbrk((wchar_t*)0, L"")), wchar_t*>::value), "");
+    static_assert((std::is_same<decltype(wcsrchr((const wchar_t*)0, L' ')), const wchar_t*>::value), "");
     static_assert((std::is_same<decltype(wcsrchr((wchar_t*)0, L' ')), wchar_t*>::value), "");
     static_assert((std::is_same<decltype(wcsspn(L"", L"")), size_t>::value), "");
+    static_assert((std::is_same<decltype(wcsstr((const wchar_t*)0, L"")), const wchar_t*>::value), "");
     static_assert((std::is_same<decltype(wcsstr((wchar_t*)0, L"")), wchar_t*>::value), "");
     static_assert((std::is_same<decltype(wcstok(ws, L"", (wchar_t**)0)), wchar_t*>::value), "");
+    static_assert((std::is_same<decltype(wmemchr((const wchar_t*)0, L' ', s)), const wchar_t*>::value), "");
     static_assert((std::is_same<decltype(wmemchr((wchar_t*)0, L' ', s)), wchar_t*>::value), "");
     static_assert((std::is_same<decltype(wmemcmp(L"", L"", s)), int>::value), "");
     static_assert((std::is_same<decltype(wmemcpy(ws, L"", s)), wchar_t*>::value), "");
@@ -105,4 +100,16 @@ int main()
     static_assert((std::is_same<decltype(wcrtomb(ns, L' ', &mb)), size_t>::value), "");
     static_assert((std::is_same<decltype(mbsrtowcs(ws, (const char**)0, s, &mb)), size_t>::value), "");
     static_assert((std::is_same<decltype(wcsrtombs(ns, (const wchar_t**)0, s, &mb)), size_t>::value), "");
+
+#ifndef _LIBCPP_HAS_NO_STDIN
+    static_assert((std::is_same<decltype(getwchar()), wint_t>::value), "");
+    static_assert((std::is_same<decltype(vwscanf(L"", va)), int>::value), "");
+    static_assert((std::is_same<decltype(wscanf(L"")), int>::value), "");
+#endif
+
+#ifndef _LIBCPP_HAS_NO_STDOUT
+    static_assert((std::is_same<decltype(putwchar(L' ')), wint_t>::value), "");
+    static_assert((std::is_same<decltype(vwprintf(L"", va)), int>::value), "");
+    static_assert((std::is_same<decltype(wprintf(L"")), int>::value), "");
+#endif
 }