diff --git a/src/libstdc++-v3/config/os/gnu/ctype_base.h b/src/libstdc++-v3/config/os/gnu/ctype_base.h
new file mode 100644
index 00000000000..955146543db
--- /dev/null
+++ b/src/libstdc++-v3/config/os/gnu/ctype_base.h
@@ -0,0 +1,66 @@
+// Locale support -*- C++ -*-
+
+// Copyright (C) 1997-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library 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, or (at your option)
+// any later version.
+
+// This library 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.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/ctype_base.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{locale}
+ */
+
+//
+// ISO C++ 14882: 22.1  Locales
+//
+
+// Information as gleaned from /usr/include/ctype.h
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /// @brief  Base class for ctype.
+  struct ctype_base
+  {
+    // Non-standard typedefs.
+    typedef const int* 		__to_type;
+
+    // NB: Offsets into ctype<char>::_M_table force a particular size
+    // on the mask type. Because of this, we don't use an enum.
+    typedef unsigned short 	mask;
+    static const mask upper    	= _ISupper;
+    static const mask lower 	= _ISlower;
+    static const mask alpha 	= _ISalpha;
+    static const mask digit 	= _ISdigit;
+    static const mask xdigit 	= _ISxdigit;
+    static const mask space 	= _ISspace;
+    static const mask print 	= _ISprint;
+    static const mask graph 	= _ISalpha | _ISdigit | _ISpunct;
+    static const mask cntrl 	= _IScntrl;
+    static const mask punct 	= _ISpunct;
+    static const mask alnum 	= _ISalpha | _ISdigit;
+#if __cplusplus >= 201103L
+    static const mask blank	= _ISblank;
+#endif
+  };
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace