+#undef _GLIBCXX_USE_WCHAR_T
+
+// Define if using setrlimit to limit memory usage during 'make check'.
+#undef _GLIBCXX_MEM_LIMITS
+
+// Define to use concept checking code from the boost libraries.
+#undef _GLIBCXX_CONCEPT_CHECKS
+
+// Define to use symbol versioning in the shared library.
+#undef _GLIBCXX_SYMVER
+
+// Define symbol versioning in assember directives. If symbol
+// versioning is beigng used, and the assembler supports this kind of
+// thing, then use it.
+// NB: _GLIBCXX_AT_AT is a hack to work around quoting issues in m4.
+#if _GLIBCXX_SYMVER
+ #define _GLIBCXX_ASM_SYMVER(cur, old, version) \
+ asm (".symver " #cur "," #old _GLIBCXX_AT_AT #version);
+#else
+ #define _GLIBCXX_ASM_SYMVER(cur, old, version)
+#endif