-// clang defines __GNUC__ but libc++ does not have tr1
-#ifndef LYX_USE_TR1
-# if __GNUC__ == 4 && !defined(USE_LLVM_LIBCPP)
-# define LYX_USE_TR1
-# endif
-#endif
+// clang defines __GNUC__ but how do the versions match?
+// disabled because of missing match_partial
+//#ifndef LYX_USE_STD_REGEX
+//# if (__GNUC__ == 4 && __GNUC_MINOR__ >= 9) || __GNUC__ > 4 || defined(USE_LLVM_LIBCPP)
+//# define LYX_USE_STD_REGEX
+//# endif
+//#endif