diff --git a/libstdc++-v3/acinclude.m4 b/libstdc++-v3/acinclude.m4
index e6723edf880..38030e432d8 100644
--- a/libstdc++-v3/acinclude.m4
+++ b/libstdc++-v3/acinclude.m4
@@ -81,6 +81,10 @@ AC_DEFUN([GLIBCXX_CONFIGURE], [
     AC_HELP_STRING([--with-newlib],
 		   [assume newlib as a system C library]))
 
+  AC_ARG_WITH([picolibc],
+    AC_HELP_STRING([--with-picolibc],
+		   [assume picolibc as a system C library]))
+
   # Will set LN_S to either 'ln -s', 'ln', or 'cp -p' (if linking isn't
   # available).  Uncomment the next line to force a particular method.
   AC_PROG_LN_S
diff --git a/libstdc++-v3/config/os/picolibc/ctype_base.h b/libstdc++-v3/config/os/picolibc/ctype_base.h
new file mode 100644
index 00000000000..bcc9e8df4a3
--- /dev/null
+++ b/libstdc++-v3/config/os/picolibc/ctype_base.h
@@ -0,0 +1,61 @@
+// Locale support for picolibc -*- C++ -*-
+
+// Copyright (C) 2000-2026 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/>.
+
+//
+// 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 short 		mask;
+    static const mask upper    	= mask (__CTYPE_UPPER);
+    static const mask lower 	= mask (__CTYPE_LOWER);
+    static const mask alpha 	= mask (__CTYPE_UPPER | __CTYPE_LOWER);
+    static const mask digit 	= mask (__CTYPE_DIGIT);
+    static const mask xdigit 	= mask (__CTYPE_HEX | __CTYPE_DIGIT);
+    static const mask space 	= mask (__CTYPE_SPACE);
+    static const mask print 	= mask (__CTYPE_PUNCT | __CTYPE_UPPER | __CTYPE_LOWER | __CTYPE_DIGIT | __CTYPE_BLANK);
+    static const mask graph 	= mask (__CTYPE_PUNCT | __CTYPE_UPPER | __CTYPE_LOWER | __CTYPE_DIGIT);
+    static const mask cntrl 	= mask (__CTYPE_CNTRL);
+    static const mask punct 	= mask (__CTYPE_PUNCT);
+    static const mask alnum 	= mask (__CTYPE_UPPER | __CTYPE_LOWER | __CTYPE_DIGIT);
+#if __cplusplus >= 201103L
+    static const mask blank 	= mask (__CTYPE_BLANK | __CTYPE_TAB);
+#endif
+  };
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
diff --git a/libstdc++-v3/config/os/picolibc/ctype_configure_char.cc b/libstdc++-v3/config/os/picolibc/ctype_configure_char.cc
new file mode 100644
index 00000000000..7b38fac2422
--- /dev/null
+++ b/libstdc++-v3/config/os/picolibc/ctype_configure_char.cc
@@ -0,0 +1,105 @@
+// Locale support for picolibc -*- C++ -*-
+
+// Copyright (C) 2011-2026 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 ctype_configure_char.cc */
+
+//
+// ISO C++ 14882: 22.1  Locales
+//
+
+#include <locale>
+#include <cstdlib>
+#include <cstring>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+// Information as gleaned from /usr/include/ctype.h
+
+  const ctype_base::mask*
+  ctype<char>::classic_table() throw()
+  { return _ctype_wide + 1; }
+
+  ctype<char>::ctype(__c_locale, const mask* __table, bool __del,
+		     size_t __refs)
+  : facet(__refs), _M_del(__table != 0 && __del),
+  _M_toupper(NULL), _M_tolower(NULL),
+  _M_table(__table ? __table : classic_table())
+  {
+    memset(_M_widen, 0, sizeof(_M_widen));
+    _M_widen_ok = 0;
+    memset(_M_narrow, 0, sizeof(_M_narrow));
+    _M_narrow_ok = 0;
+  }
+
+  ctype<char>::ctype(const mask* __table, bool __del, size_t __refs)
+  : facet(__refs), _M_del(__table != 0 && __del),
+  _M_toupper(NULL), _M_tolower(NULL),
+  _M_table(__table ? __table : classic_table())
+  {
+    memset(_M_widen, 0, sizeof(_M_widen));
+    _M_widen_ok = 0;
+    memset(_M_narrow, 0, sizeof(_M_narrow));
+    _M_narrow_ok = 0;
+  }
+
+  char
+  ctype<char>::do_toupper(char __c) const
+  {
+    int __x = __c;
+    return (this->is(ctype_base::lower, __c) ? (__x - 'a' + 'A') : __x);
+  }
+
+  const char*
+  ctype<char>::do_toupper(char* __low, const char* __high) const
+  {
+    while (__low < __high)
+      {
+	*__low = this->do_toupper(*__low);
+	++__low;
+      }
+    return __high;
+  }
+
+  char
+  ctype<char>::do_tolower(char __c) const
+  {
+    int __x = __c;
+    return (this->is(ctype_base::upper, __c) ? (__x - 'A' + 'a') : __x);
+  }
+
+  const char*
+  ctype<char>::do_tolower(char* __low, const char* __high) const
+  {
+    while (__low < __high)
+      {
+	*__low = this->do_tolower(*__low);
+	++__low;
+      }
+    return __high;
+  }
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
diff --git a/libstdc++-v3/config/os/picolibc/ctype_inline.h b/libstdc++-v3/config/os/picolibc/ctype_inline.h
new file mode 100644
index 00000000000..7903214883b
--- /dev/null
+++ b/libstdc++-v3/config/os/picolibc/ctype_inline.h
@@ -0,0 +1,74 @@
+// Locale support for picolibc -*- C++ -*-
+
+// Copyright (C) 2000-2026 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_inline.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
+//
+
+// ctype bits to be inlined go here. Non-inlinable (ie virtual do_*)
+// functions go in ctype.cc
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  bool
+  ctype<char>::
+  is(mask __m, char __c) const
+  { return _M_table[static_cast<unsigned char>(__c)] & __m; }
+
+  const char*
+  ctype<char>::
+  is(const char* __low, const char* __high, mask* __vec) const
+  {
+    while (__low < __high)
+      *__vec++ = _M_table[static_cast<unsigned char>(*__low++)];
+    return __high;
+  }
+
+  const char*
+  ctype<char>::
+  scan_is(mask __m, const char* __low, const char* __high) const
+  {
+    while (__low < __high && !this->is(__m, *__low))
+      ++__low;
+    return __low;
+  }
+
+  const char*
+  ctype<char>::
+  scan_not(mask __m, const char* __low, const char* __high) const
+  {
+    while (__low < __high && this->is(__m, *__low) != 0)
+      ++__low;
+    return __low;
+  }
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
diff --git a/libstdc++-v3/config/os/picolibc/os_defines.h b/libstdc++-v3/config/os/picolibc/os_defines.h
new file mode 100644
index 00000000000..e9c611b4fb5
--- /dev/null
+++ b/libstdc++-v3/config/os/picolibc/os_defines.h
@@ -0,0 +1,36 @@
+// Specific definitions for picolibc -*- C++ -*-
+
+// Copyright (C) 2026 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/os_defines.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{iosfwd}
+ */
+
+#ifndef _GLIBCXX_OS_DEFINES
+#define _GLIBCXX_OS_DEFINES 1
+
+// System-specific #define, typedefs, corrections, etc, go here.  This
+// file will come before all others.
+
+#endif
diff --git a/libstdc++-v3/configure b/libstdc++-v3/configure
index 3d825a69fa2..4f144382e1b 100755
--- a/libstdc++-v3/configure
+++ b/libstdc++-v3/configure
@@ -922,6 +922,7 @@ enable_largefile
 with_target_subdir
 with_cross_host
 with_newlib
+with_picolibc
 enable_maintainer_mode
 enable_shared
 enable_static
@@ -1698,6 +1699,7 @@ Optional Packages:
                           configuring in a subdirectory
   --with-cross-host=HOST  configuring with a cross compiler
   --with-newlib           assume newlib as a system C library
+  --with-picolibc         assume picolibc as a system C library
   --with-pic              try to use only PIC/non-PIC objects [default=use
                           both]
   --with-gnu-ld           assume the C compiler uses GNU ld [default=no]
@@ -5572,6 +5574,13 @@ if test "${with_newlib+set}" = set; then :
 fi
 
 
+
+# Check whether --with-picolibc was given.
+if test "${with_picolibc+set}" = set; then :
+  withval=$with_picolibc;
+fi
+
+
   # Will set LN_S to either 'ln -s', 'ln', or 'cp -p' (if linking isn't
   # available).  Uncomment the next line to force a particular method.
   { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether ln -s works" >&5
@@ -5944,6 +5953,7 @@ $as_echo "$as_me: OS config directory is $os_include_dir" >&6;}
 
 # Libtool setup.
 if test "x${with_newlib}" != "xyes" &&
+    test "x${with_picolibc}" != "xyes" &&
     test "x${with_avrlibc}" != "xyes" &&
     test "x$with_headers" != "xno"; then
   enable_dlopen=yes
@@ -12669,7 +12679,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<_LT_EOF
-#line 12672 "configure"
+#line 12682 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -12775,7 +12785,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<_LT_EOF
-#line 12778 "configure"
+#line 12788 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -16458,7 +16468,7 @@ $as_echo "$glibcxx_cv_atomic_word" >&6; }
     # Fake what AC_TRY_COMPILE does.
 
     cat > conftest.$ac_ext << EOF
-#line 16461 "configure"
+#line 16471 "configure"
 #include "${glibcxx_srcdir}/config/$atomic_word_dir/atomic_word.h"
 int main()
 {
@@ -16604,7 +16614,7 @@ $as_echo "mutex" >&6; }
   # unnecessary for this test.
 
     cat > conftest.$ac_ext << EOF
-#line 16607 "configure"
+#line 16617 "configure"
 int main()
 {
   _Decimal32 d1;
@@ -16646,7 +16656,7 @@ ac_compiler_gnu=$ac_cv_cxx_compiler_gnu
   # unnecessary for this test.
 
   cat > conftest.$ac_ext << EOF
-#line 16649 "configure"
+#line 16659 "configure"
 template<typename T1, typename T2>
   struct same
   { typedef T2 type; };
@@ -28831,6 +28841,136 @@ rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
         glibcxx_cv_mkdir=yes
         ;;
     esac
+  elif test "x${with_picolibc}" = "xyes"; then
+    os_include_dir="os/picolibc"
+    $as_echo "#define HAVE_HYPOT 1" >>confdefs.h
+
+
+    # GLIBCXX_CHECK_STDLIB_SUPPORT
+    $as_echo "#define HAVE_STRTOF 1" >>confdefs.h
+
+
+    $as_echo "#define HAVE_ACOSF 1" >>confdefs.h
+
+    $as_echo "#define HAVE_ASINF 1" >>confdefs.h
+
+    $as_echo "#define HAVE_ATAN2F 1" >>confdefs.h
+
+    $as_echo "#define HAVE_ATANF 1" >>confdefs.h
+
+    $as_echo "#define HAVE_CEILF 1" >>confdefs.h
+
+    $as_echo "#define HAVE_COSF 1" >>confdefs.h
+
+    $as_echo "#define HAVE_COSHF 1" >>confdefs.h
+
+    $as_echo "#define HAVE_EXPF 1" >>confdefs.h
+
+    $as_echo "#define HAVE_FABSF 1" >>confdefs.h
+
+    $as_echo "#define HAVE_FLOORF 1" >>confdefs.h
+
+    $as_echo "#define HAVE_FMODF 1" >>confdefs.h
+
+    $as_echo "#define HAVE_FREXPF 1" >>confdefs.h
+
+    $as_echo "#define HAVE_HYPOTF 1" >>confdefs.h
+
+    $as_echo "#define HAVE_LDEXPF 1" >>confdefs.h
+
+    $as_echo "#define HAVE_LOG10F 1" >>confdefs.h
+
+    $as_echo "#define HAVE_LOGF 1" >>confdefs.h
+
+    $as_echo "#define HAVE_MODFF 1" >>confdefs.h
+
+    $as_echo "#define HAVE_POWF 1" >>confdefs.h
+
+    $as_echo "#define HAVE_SINF 1" >>confdefs.h
+
+    $as_echo "#define HAVE_SINHF 1" >>confdefs.h
+
+    $as_echo "#define HAVE_SQRTF 1" >>confdefs.h
+
+    $as_echo "#define HAVE_TANF 1" >>confdefs.h
+
+    $as_echo "#define HAVE_TANHF 1" >>confdefs.h
+
+
+    # Support for iconv in picolibc is configurable.
+    cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#include <picolibc.h>
+int
+main ()
+{
+
+      #ifndef _ICONV_ENABLED
+      #error
+      #endif
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+  ac_picolibc_iconv_enabled=yes
+else
+  ac_picolibc_iconv_enabled=no
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+    if test "$ac_picolibc_iconv_enabled" = yes; then
+      $as_echo "#define HAVE_ICONV 1" >>confdefs.h
+
+    fi
+
+    $as_echo "#define HAVE_MEMALIGN 1" >>confdefs.h
+
+
+    # Check for TLS
+    cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#include <picolibc.h>
+int
+main ()
+{
+
+      #ifndef __THREAD_LOCAL_STORAGE
+      #error
+      #endif
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+  ac_picolibc_tls_enabled=yes
+else
+  ac_picolibc_tls_enabled=no
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+    if test "$ac_picolibc_tls_enabled" = yes; then
+      $as_echo "#define HAVE_TLS 1" >>confdefs.h
+
+    fi
+
+    $as_echo "#define HAVE_ALIGNED_ALLOC 1" >>confdefs.h
+
+    $as_echo "#define HAVE_AT_QUICK_EXIT 1" >>confdefs.h
+
+    $as_echo "#define HAVE_LINK 1" >>confdefs.h
+
+    $as_echo "#define HAVE_SYS_STAT_H 1" >>confdefs.h
+
+    $as_echo "#define HAVE_SYS_TYPES_H 1" >>confdefs.h
+
+    $as_echo "#define HAVE_SETENV 1" >>confdefs.h
+
+    $as_echo "#define HAVE_STRERROR_L 1" >>confdefs.h
+
+    $as_echo "#define HAVE_S_ISREG 1" >>confdefs.h
+
+    $as_echo "#define HAVE_UNISTD_H 1" >>confdefs.h
+
+
   elif test "x$with_headers" != "xno"; then
 
 # Base decisions on target environment.
@@ -54005,7 +54145,7 @@ $as_echo "$glibcxx_cv_libbacktrace_atomics" >&6; }
     CXXFLAGS='-O0 -S'
 
     cat > conftest.$ac_ext << EOF
-#line 54008 "configure"
+#line 54148 "configure"
 #include <stddef.h>
 int main()
 {
diff --git a/libstdc++-v3/configure.ac b/libstdc++-v3/configure.ac
index 339e7bb17a4..f81dccdeef7 100644
--- a/libstdc++-v3/configure.ac
+++ b/libstdc++-v3/configure.ac
@@ -100,6 +100,7 @@ GLIBCXX_CONFIGURE
 
 # Libtool setup.
 if test "x${with_newlib}" != "xyes" &&
+    test "x${with_picolibc}" != "xyes" &&
     test "x${with_avrlibc}" != "xyes" &&
     test "x$with_headers" != "xno"; then
   AC_LIBTOOL_DLOPEN
@@ -428,6 +429,67 @@ dnl # rather than hardcoding that information.
         glibcxx_cv_mkdir=yes
         ;;
     esac
+  elif test "x${with_picolibc}" = "xyes"; then
+    os_include_dir="os/picolibc"
+    AC_DEFINE(HAVE_HYPOT)
+
+    # GLIBCXX_CHECK_STDLIB_SUPPORT
+    AC_DEFINE(HAVE_STRTOF)
+
+    AC_DEFINE(HAVE_ACOSF)
+    AC_DEFINE(HAVE_ASINF)
+    AC_DEFINE(HAVE_ATAN2F)
+    AC_DEFINE(HAVE_ATANF)
+    AC_DEFINE(HAVE_CEILF)
+    AC_DEFINE(HAVE_COSF)
+    AC_DEFINE(HAVE_COSHF)
+    AC_DEFINE(HAVE_EXPF)
+    AC_DEFINE(HAVE_FABSF)
+    AC_DEFINE(HAVE_FLOORF)
+    AC_DEFINE(HAVE_FMODF)
+    AC_DEFINE(HAVE_FREXPF)
+    AC_DEFINE(HAVE_HYPOTF)
+    AC_DEFINE(HAVE_LDEXPF)
+    AC_DEFINE(HAVE_LOG10F)
+    AC_DEFINE(HAVE_LOGF)
+    AC_DEFINE(HAVE_MODFF)
+    AC_DEFINE(HAVE_POWF)
+    AC_DEFINE(HAVE_SINF)
+    AC_DEFINE(HAVE_SINHF)
+    AC_DEFINE(HAVE_SQRTF)
+    AC_DEFINE(HAVE_TANF)
+    AC_DEFINE(HAVE_TANHF)
+
+    # Support for iconv in picolibc is configurable.
+    AC_TRY_COMPILE([#include <picolibc.h>], [
+      #ifndef _ICONV_ENABLED
+      #error
+      #endif], [ac_picolibc_iconv_enabled=yes], [ac_picolibc_iconv_enabled=no])
+    if test "$ac_picolibc_iconv_enabled" = yes; then
+      AC_DEFINE(HAVE_ICONV)
+    fi
+
+    AC_DEFINE(HAVE_MEMALIGN)
+
+    # Check for TLS
+    AC_TRY_COMPILE([#include <picolibc.h>], [
+      #ifndef __THREAD_LOCAL_STORAGE
+      #error
+      #endif], [ac_picolibc_tls_enabled=yes], [ac_picolibc_tls_enabled=no])
+    if test "$ac_picolibc_tls_enabled" = yes; then
+      AC_DEFINE(HAVE_TLS)
+    fi
+
+    AC_DEFINE(HAVE_ALIGNED_ALLOC)
+    AC_DEFINE(HAVE_AT_QUICK_EXIT)
+    AC_DEFINE(HAVE_LINK)
+    AC_DEFINE(HAVE_SYS_STAT_H)
+    AC_DEFINE(HAVE_SYS_TYPES_H)
+    AC_DEFINE(HAVE_SETENV)
+    AC_DEFINE(HAVE_STRERROR_L)
+    AC_DEFINE(HAVE_S_ISREG)
+    AC_DEFINE(HAVE_UNISTD_H)
+
   elif test "x$with_headers" != "xno"; then
     GLIBCXX_CROSSCONFIG
   fi