diff --git a/gnu/lib/libstdc++/c++config.h b/gnu/lib/libstdc++/c++config.h
index 58bcb2457541..b630940bda1b 100644
--- a/gnu/lib/libstdc++/c++config.h
+++ b/gnu/lib/libstdc++/c++config.h
@@ -104,7 +104,7 @@ libstdc++-v3/include/bits/c++config before full recompilation of the library.
 #define _GLIBCPP_USE_C99 1
 
 // Define if code specialized for wchar_t should be used.
-/* #undef _GLIBCPP_USE_WCHAR_T */
+#define _GLIBCPP_USE_WCHAR_T 1
 
 // Define if using setrlimit to limit memory usage during 'make check'.
 /* #undef _GLIBCPP_MEM_LIMITS */
diff --git a/gnu/lib/libstdc++/config.h b/gnu/lib/libstdc++/config.h
index 7cf13d10a6c2..f8a228a89d7e 100644
--- a/gnu/lib/libstdc++/config.h
+++ b/gnu/lib/libstdc++/config.h
@@ -16,7 +16,7 @@
 #define _GLIBCPP_USE_C99 1
 
 // Define if code specialized for wchar_t should be used.
-/* #undef _GLIBCPP_USE_WCHAR_T */
+#define _GLIBCPP_USE_WCHAR_T 1
 
 // Define if using setrlimit to limit memory usage during 'make check'.
 /* #undef _GLIBCPP_MEM_LIMITS */