diff --git a/libcxx/include/__config b/libcxx/include/__config
--- a/libcxx/include/__config
+++ b/libcxx/include/__config
@@ -293,7 +293,6 @@
 #  if (defined(_M_AMD64) || defined(__x86_64__)) || (defined(_M_ARM) || defined(__arm__))
 #    define _LIBCPP_HAS_BITSCAN64
 #  endif
-#  define _LIBCPP_HAS_OPEN_WITH_WCHAR
 #  if defined(_LIBCPP_MSVCRT)
 #    define _LIBCPP_HAS_QUICK_EXIT
 #  endif
diff --git a/libcxx/include/fstream b/libcxx/include/fstream
--- a/libcxx/include/fstream
+++ b/libcxx/include/fstream
@@ -231,9 +231,7 @@
     _LIBCPP_INLINE_VISIBILITY
     bool is_open() const;
     basic_filebuf* open(const char* __s, ios_base::openmode __mode);
-#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
-    basic_filebuf* open(const wchar_t* __s, ios_base::openmode __mode);
-#endif
+    basic_filebuf* open(const wchar_t* __s, ios_base::openmode __mode); // EXTENSION
     _LIBCPP_INLINE_VISIBILITY
     basic_filebuf* open(const string& __s, ios_base::openmode __mode);
 
@@ -591,12 +589,11 @@
   return __rt;
 }
 
-#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
 // This is basically the same as the char* overload except that it uses _wfopen
 // and long mode strings.
 template <class _CharT, class _Traits>
 basic_filebuf<_CharT, _Traits>*
-basic_filebuf<_CharT, _Traits>::open(const wchar_t* __s, ios_base::openmode __mode)
+basic_filebuf<_CharT, _Traits>::open(const wchar_t* __s, ios_base::openmode __mode) // EXTENSION
 {
     basic_filebuf<_CharT, _Traits>* __rt = nullptr;
     if (__file_ == nullptr)
@@ -673,7 +670,6 @@
     }
     return __rt;
 }
-#endif
 
 template <class _CharT, class _Traits>
 inline
@@ -1139,10 +1135,8 @@
     basic_ifstream();
     _LIBCPP_INLINE_VISIBILITY
     explicit basic_ifstream(const char* __s, ios_base::openmode __mode = ios_base::in);
-#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
     _LIBCPP_INLINE_VISIBILITY
-    explicit basic_ifstream(const wchar_t* __s, ios_base::openmode __mode = ios_base::in);
-#endif
+    explicit basic_ifstream(const wchar_t* __s, ios_base::openmode __mode = ios_base::in); // EXTENSION
     _LIBCPP_INLINE_VISIBILITY
     explicit basic_ifstream(const string& __s, ios_base::openmode __mode = ios_base::in);
 #if _LIBCPP_STD_VER >= 17 && !defined(_LIBCPP_HAS_NO_FILESYSTEM_LIBRARY)
@@ -1162,9 +1156,7 @@
     _LIBCPP_INLINE_VISIBILITY
     bool is_open() const;
     void open(const char* __s, ios_base::openmode __mode = ios_base::in);
-#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
-    void open(const wchar_t* __s, ios_base::openmode __mode = ios_base::in);
-#endif
+    void open(const wchar_t* __s, ios_base::openmode __mode = ios_base::in); // EXTENSION
     void open(const string& __s, ios_base::openmode __mode = ios_base::in);
 #if _LIBCPP_STD_VER >= 17 && !defined(_LIBCPP_HAS_NO_FILESYSTEM_LIBRARY)
     _LIBCPP_AVAILABILITY_FILESYSTEM _LIBCPP_INLINE_VISIBILITY
@@ -1199,16 +1191,14 @@
         this->setstate(ios_base::failbit);
 }
 
-#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
 template <class _CharT, class _Traits>
 inline
-basic_ifstream<_CharT, _Traits>::basic_ifstream(const wchar_t* __s, ios_base::openmode __mode)
+basic_ifstream<_CharT, _Traits>::basic_ifstream(const wchar_t* __s, ios_base::openmode __mode) // EXTENSION
     : basic_istream<char_type, traits_type>(&__sb_)
 {
     if (__sb_.open(__s, __mode | ios_base::in) == nullptr)
         this->setstate(ios_base::failbit);
 }
-#endif
 
 template <class _CharT, class _Traits>
 inline
@@ -1281,17 +1271,15 @@
         this->setstate(ios_base::failbit);
 }
 
-#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
 template <class _CharT, class _Traits>
 void
-basic_ifstream<_CharT, _Traits>::open(const wchar_t* __s, ios_base::openmode __mode)
+basic_ifstream<_CharT, _Traits>::open(const wchar_t* __s, ios_base::openmode __mode) // EXTENSION
 {
     if (__sb_.open(__s, __mode | ios_base::in))
         this->clear();
     else
         this->setstate(ios_base::failbit);
 }
-#endif
 
 template <class _CharT, class _Traits>
 void
@@ -1339,10 +1327,8 @@
     basic_ofstream();
     _LIBCPP_INLINE_VISIBILITY
     explicit basic_ofstream(const char* __s, ios_base::openmode __mode = ios_base::out);
-#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
     _LIBCPP_INLINE_VISIBILITY
-    explicit basic_ofstream(const wchar_t* __s, ios_base::openmode __mode = ios_base::out);
-#endif
+    explicit basic_ofstream(const wchar_t* __s, ios_base::openmode __mode = ios_base::out); // EXTENSION
     _LIBCPP_INLINE_VISIBILITY
     explicit basic_ofstream(const string& __s, ios_base::openmode __mode = ios_base::out);
 
@@ -1364,9 +1350,7 @@
     _LIBCPP_INLINE_VISIBILITY
     bool is_open() const;
     void open(const char* __s, ios_base::openmode __mode = ios_base::out);
-#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
-    void open(const wchar_t* __s, ios_base::openmode __mode = ios_base::out);
-#endif
+    void open(const wchar_t* __s, ios_base::openmode __mode = ios_base::out); // EXTENSION
     void open(const string& __s, ios_base::openmode __mode = ios_base::out);
 
 #if _LIBCPP_STD_VER >= 17 && !defined(_LIBCPP_HAS_NO_FILESYSTEM_LIBRARY)
@@ -1400,16 +1384,14 @@
         this->setstate(ios_base::failbit);
 }
 
-#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
 template <class _CharT, class _Traits>
 inline
-basic_ofstream<_CharT, _Traits>::basic_ofstream(const wchar_t* __s, ios_base::openmode __mode)
+basic_ofstream<_CharT, _Traits>::basic_ofstream(const wchar_t* __s, ios_base::openmode __mode) // EXTENSION
     : basic_ostream<char_type, traits_type>(&__sb_)
 {
     if (__sb_.open(__s, __mode | ios_base::out) == nullptr)
         this->setstate(ios_base::failbit);
 }
-#endif
 
 template <class _CharT, class _Traits>
 inline
@@ -1482,17 +1464,15 @@
         this->setstate(ios_base::failbit);
 }
 
-#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
 template <class _CharT, class _Traits>
 void
-basic_ofstream<_CharT, _Traits>::open(const wchar_t* __s, ios_base::openmode __mode)
+basic_ofstream<_CharT, _Traits>::open(const wchar_t* __s, ios_base::openmode __mode) // EXTENSION
 {
     if (__sb_.open(__s, __mode | ios_base::out))
         this->clear();
     else
         this->setstate(ios_base::failbit);
 }
-#endif
 
 template <class _CharT, class _Traits>
 void
@@ -1540,10 +1520,8 @@
     basic_fstream();
     _LIBCPP_INLINE_VISIBILITY
     explicit basic_fstream(const char* __s, ios_base::openmode __mode = ios_base::in | ios_base::out);
-#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
     _LIBCPP_INLINE_VISIBILITY
-    explicit basic_fstream(const wchar_t* __s, ios_base::openmode __mode = ios_base::in | ios_base::out);
-#endif
+    explicit basic_fstream(const wchar_t* __s, ios_base::openmode __mode = ios_base::in | ios_base::out); // EXTENSION
     _LIBCPP_INLINE_VISIBILITY
     explicit basic_fstream(const string& __s, ios_base::openmode __mode = ios_base::in | ios_base::out);
 
@@ -1567,9 +1545,7 @@
     _LIBCPP_INLINE_VISIBILITY
     bool is_open() const;
     void open(const char* __s, ios_base::openmode __mode = ios_base::in | ios_base::out);
-#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
-    void open(const wchar_t* __s, ios_base::openmode __mode = ios_base::in | ios_base::out);
-#endif
+    void open(const wchar_t* __s, ios_base::openmode __mode = ios_base::in | ios_base::out); // EXTENSION
     void open(const string& __s, ios_base::openmode __mode = ios_base::in | ios_base::out);
 
 #if _LIBCPP_STD_VER >= 17 && !defined(_LIBCPP_HAS_NO_FILESYSTEM_LIBRARY)
@@ -1601,16 +1577,14 @@
         this->setstate(ios_base::failbit);
 }
 
-#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
 template <class _CharT, class _Traits>
 inline
-basic_fstream<_CharT, _Traits>::basic_fstream(const wchar_t* __s, ios_base::openmode __mode)
+basic_fstream<_CharT, _Traits>::basic_fstream(const wchar_t* __s, ios_base::openmode __mode) // EXTENSION
     : basic_iostream<char_type, traits_type>(&__sb_)
 {
     if (__sb_.open(__s, __mode) == nullptr)
         this->setstate(ios_base::failbit);
 }
-#endif
 
 template <class _CharT, class _Traits>
 inline
@@ -1683,17 +1657,15 @@
         this->setstate(ios_base::failbit);
 }
 
-#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
 template <class _CharT, class _Traits>
 void
-basic_fstream<_CharT, _Traits>::open(const wchar_t* __s, ios_base::openmode __mode)
+basic_fstream<_CharT, _Traits>::open(const wchar_t* __s, ios_base::openmode __mode) // EXTENSION
 {
     if (__sb_.open(__s, __mode))
         this->clear();
     else
         this->setstate(ios_base::failbit);
 }
-#endif
 
 template <class _CharT, class _Traits>
 void
diff --git a/libcxx/test/libcxx/input.output/file.streams/fstreams/fstream.cons/wchar_pointer.pass.cpp b/libcxx/test/libcxx/input.output/file.streams/fstreams/fstream.cons/wchar_pointer.pass.cpp
--- a/libcxx/test/libcxx/input.output/file.streams/fstreams/fstream.cons/wchar_pointer.pass.cpp
+++ b/libcxx/test/libcxx/input.output/file.streams/fstreams/fstream.cons/wchar_pointer.pass.cpp
@@ -20,7 +20,6 @@
 
 int main(int, char**)
 {
-#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
     std::wstring temp = get_wide_temp_file_name();
     {
         std::fstream fs(temp.c_str(), std::ios_base::in | std::ios_base::out
@@ -42,7 +41,6 @@
         assert(x == 3.25);
     }
     _wremove(temp.c_str());
-#endif
 
-  return 0;
+    return 0;
 }
diff --git a/libcxx/test/libcxx/input.output/file.streams/fstreams/fstream.members/open_wchar_pointer.pass.cpp b/libcxx/test/libcxx/input.output/file.streams/fstreams/fstream.members/open_wchar_pointer.pass.cpp
--- a/libcxx/test/libcxx/input.output/file.streams/fstreams/fstream.members/open_wchar_pointer.pass.cpp
+++ b/libcxx/test/libcxx/input.output/file.streams/fstreams/fstream.members/open_wchar_pointer.pass.cpp
@@ -20,7 +20,6 @@
 
 int main(int, char**)
 {
-#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
     std::wstring temp = get_wide_temp_file_name();
     {
         std::fstream fs;
@@ -48,7 +47,6 @@
         assert(x == 3.25);
     }
     _wremove(temp.c_str());
-#endif
 
-  return 0;
+    return 0;
 }
diff --git a/libcxx/test/libcxx/input.output/file.streams/fstreams/ifstream.cons/wchar_pointer.pass.cpp b/libcxx/test/libcxx/input.output/file.streams/fstreams/ifstream.cons/wchar_pointer.pass.cpp
--- a/libcxx/test/libcxx/input.output/file.streams/fstreams/ifstream.cons/wchar_pointer.pass.cpp
+++ b/libcxx/test/libcxx/input.output/file.streams/fstreams/ifstream.cons/wchar_pointer.pass.cpp
@@ -22,7 +22,6 @@
 
 int main(int, char**)
 {
-#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
     {
         std::ifstream fs(L"test.dat");
         double x = 0;
@@ -41,7 +40,6 @@
     // std::wifstream(const wchar_t*, std::ios_base::openmode) is tested in
     // test/libcxx/input.output/file.streams/fstreams/ofstream.cons/wchar_pointer.pass.cpp
     // which creates writable files.
-#endif
 
-  return 0;
+    return 0;
 }
diff --git a/libcxx/test/libcxx/input.output/file.streams/fstreams/ifstream.members/open_wchar_pointer.pass.cpp b/libcxx/test/libcxx/input.output/file.streams/fstreams/ifstream.members/open_wchar_pointer.pass.cpp
--- a/libcxx/test/libcxx/input.output/file.streams/fstreams/ifstream.members/open_wchar_pointer.pass.cpp
+++ b/libcxx/test/libcxx/input.output/file.streams/fstreams/ifstream.members/open_wchar_pointer.pass.cpp
@@ -22,7 +22,6 @@
 
 int main(int, char**)
 {
-#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
     {
         std::ifstream fs;
         assert(!fs.is_open());
@@ -47,7 +46,6 @@
         fs >> c;
         assert(c == L'r');
     }
-#endif
 
-  return 0;
+    return 0;
 }
diff --git a/libcxx/test/libcxx/input.output/file.streams/fstreams/ofstream.cons/wchar_pointer.pass.cpp b/libcxx/test/libcxx/input.output/file.streams/fstreams/ofstream.cons/wchar_pointer.pass.cpp
--- a/libcxx/test/libcxx/input.output/file.streams/fstreams/ofstream.cons/wchar_pointer.pass.cpp
+++ b/libcxx/test/libcxx/input.output/file.streams/fstreams/ofstream.cons/wchar_pointer.pass.cpp
@@ -20,7 +20,6 @@
 
 int main(int, char**)
 {
-#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
     std::wstring temp = get_wide_temp_file_name();
     {
         std::ofstream fs(temp.c_str());
@@ -56,7 +55,6 @@
         assert(x == 3.25);
     }
     _wremove(temp.c_str());
-#endif
 
-  return 0;
+    return 0;
 }
diff --git a/libcxx/test/libcxx/input.output/file.streams/fstreams/ofstream.members/open_wchar_pointer.pass.cpp b/libcxx/test/libcxx/input.output/file.streams/fstreams/ofstream.members/open_wchar_pointer.pass.cpp
--- a/libcxx/test/libcxx/input.output/file.streams/fstreams/ofstream.members/open_wchar_pointer.pass.cpp
+++ b/libcxx/test/libcxx/input.output/file.streams/fstreams/ofstream.members/open_wchar_pointer.pass.cpp
@@ -20,7 +20,6 @@
 
 int main(int, char**)
 {
-#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
     std::wstring temp = get_wide_temp_file_name();
     {
         std::ofstream fs;
@@ -56,7 +55,6 @@
         assert(c == L'a');
     }
     _wremove(temp.c_str());
-#endif
 
-  return 0;
+    return 0;
 }
diff --git a/libcxx/test/support/platform_support.h b/libcxx/test/support/platform_support.h
--- a/libcxx/test/support/platform_support.h
+++ b/libcxx/test/support/platform_support.h
@@ -89,14 +89,12 @@
 #endif
 }
 
-#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
 inline
 std::wstring get_wide_temp_file_name()
 {
     return std::wstring_convert<std::codecvt_utf8_utf16<wchar_t> >().from_bytes(
         get_temp_file_name());
 }
-#endif // _LIBCPP_HAS_OPEN_WITH_WCHAR
 
 #if defined(_CS_GNU_LIBC_VERSION)
 inline bool glibc_version_less_than(char const* version) {