PR libstdc++/68353 fix _GLIBCXX_USE_C99_WCHAR test

	PR libstdc++/68353
	* include/bits/basic_string.h: Test value of _GLIBCXX_USE_C99_WCHAR
	not whether it is defined.
	* include/ext/vstring.h: Likewise.

From-SVN: r230395

libstdc++-v3/ChangeLog

+2015-11-15  Jonathan Wakely  <jwakely@redhat.com>
+
+	PR libstdc++/68353
+	* include/bits/basic_string.h: Test value of _GLIBCXX_USE_C99_WCHAR
+	not whether it is defined.
+	* include/ext/vstring.h: Likewise.
+
 2015-11-14  Andreas Tobler  <andreast@gcc.gnu.org>
 
 	* acinclude.m4 (GLIBCXX_ENABLE_CLOCALE): Change locale implementation

libstdc++-v3/include/bits/basic_string.h

@@ -5503,7 +5503,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11
   }
 #endif // _GLIBCXX_USE_C99_STDIO
 
-#if defined(_GLIBCXX_USE_WCHAR_T) && defined(_GLIBCXX_USE_C99_WCHAR)
+#if defined(_GLIBCXX_USE_WCHAR_T) && _GLIBCXX_USE_C99_WCHAR
   inline int 
   stoi(const wstring& __str, size_t* __idx = 0, int __base = 10)
   { return __gnu_cxx::__stoa<long, int>(&std::wcstol, "stoi", __str.c_str(),

libstdc++-v3/include/ext/vstring.h

@@ -2794,7 +2794,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
   }
 #endif // _GLIBCXX_USE_C99_STDIO
 
-#if defined(_GLIBCXX_USE_WCHAR_T) && defined(_GLIBCXX_USE_C99_WCHAR)
+#if defined(_GLIBCXX_USE_WCHAR_T) && _GLIBCXX_USE_C99_WCHAR
   inline int 
   stoi(const __wvstring& __str, std::size_t* __idx = 0, int __base = 10)
   { return __gnu_cxx::__stoa<long, int>(&std::wcstol, "stoi", __str.c_str(),