libcxxrt defines bad_array_new_length::what() so move that into a conditional compilation block

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@221025 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/src/new.cpp b/src/new.cpp
index 2fb6e7f..2b37601 100644
--- a/src/new.cpp
+++ b/src/new.cpp
@@ -200,6 +200,12 @@
 {
 }
 
+const char*
+bad_array_new_length::what() const _NOEXCEPT
+{
+    return "bad_array_new_length";
+}
+
 #endif //LIBCXXRT
 
 const char*
@@ -216,12 +222,6 @@
 {
 }
 
-const char*
-bad_array_new_length::what() const _NOEXCEPT
-{
-    return "bad_array_new_length";
-}
-
 #endif // _LIBCPPABI_VERSION
 
 #ifndef LIBSTDCXX