message: XPath: Throw std::bad_alloc if we got an out-of-memory error
  This allows us to gradually convert exception handling of out-of-memory
  during evaluation to a non-throwing approach without changing the
  observable behavior.
diff: @@ -11870,6 +11870,10 @@ PUGI__NS_BEGIN
  xpath_string r = impl->root->eval_string(c, sd.stack);
  + #ifndef PUGIXML_NO_EXCEPTIONS
  + if (sd.error) throw std::bad_alloc();
  + #endif
  +
  return sd.error ? xpath_string() : r;
  }
  @@ -12510,6 +12514,10 @@ namespace pugi
  bool r = static_cast<impl::xpath_query_impl*>(_impl)->root->eval_boolean(c, sd.stack);
  + #ifndef PUGIXML_NO_EXCEPTIONS
  + if (sd.error) throw std::bad_alloc();
  + #endif
  +
  return sd.error ? false : r;
  }
  @@ -12526,6 +12534,10 @@ namespace pugi
  double r = static_cast<impl::xpath_query_impl*>(_impl)->root->eval_number(c, sd.stack);
  + #ifndef PUGIXML_NO_EXCEPTIONS
  + if (sd.error) throw std::bad_alloc();
  + #endif
  +
  return sd.error ? impl::gen_nan() : r;
  }
  @@ -12574,6 +12586,10 @@ namespace pugi
  impl::xpath_node_set_raw r = root->eval_node_set(c, sd.stack, impl::nodeset_eval_all);
  + #ifndef PUGIXML_NO_EXCEPTIONS
  + if (sd.error) throw std::bad_alloc();
  + #endif
  +
  return sd.error ? xpath_node_set() : xpath_node_set(r.begin(), r.end(), r.type());
  }
  @@ -12591,6 +12607,10 @@ namespace pugi
  impl::xpath_node_set_raw r = root->eval_node_set(c, sd.stack, impl::nodeset_eval_first);
  + #ifndef PUGIXML_NO_EXCEPTIONS
  + if (sd.error) throw std::bad_alloc();
  + #endif
  +
  return sd.error ? xpath_node() : r.first();
  }
  