Undo some overzealous #ifdefs for LIBCXXRT.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@152718 91177308-0d34-0410-b5e6-96231b3b80d8

src/exception.cpp

@@ -114,22 +114,26 @@ exception::~exception() _NOEXCEPT
 {
 }
 
-bad_exception::~bad_exception() _NOEXCEPT
-{
-}
-
 const char* exception::what() const _NOEXCEPT
 {
   return "std::exception";
 }
 
+#endif  // _LIBCPPABI_VERSION
+#endif //LIBCXXRT
+#ifndef _LIBCPPABI_VERSION
+
+bad_exception::~bad_exception() _NOEXCEPT
+{
+}
+
 const char* bad_exception::what() const _NOEXCEPT
 {
   return "std::bad_exception";
 }
 
-#endif  // _LIBCPPABI_VERSION
-#endif //LIBCXXRT
+#endif
+
 
 exception_ptr::~exception_ptr() _NOEXCEPT
 {