message: Fix C++11 build with explicit constructor for VisualizeWhitespace.
diff: @@ -40,12 +40,23 @@ std::ostream& operator<<(std::ostream&, const AutoTruncate& trunc);
  // To help visualize strings that consist of whitespace, this stream adapter
  // prints spaces, tabs, and newlines with alternate text, without modifying or
  // copying the original string.
  +//
  +// usage: stream << VisualizeWhitespace(text_with_lots_of_spaces);
  struct VisualizeWhitespace {
  const absl::string_view text; // original text to be printed
  - const char space_alt = '.'; // spaces replacement
  - const absl::string_view newline_alt = "\\\n"; // newline replacement
  - const absl::string_view tab_alt = "#"; // tab replacement
  + const char space_alt; // spaces replacement
  + const absl::string_view newline_alt; // newline replacement
  + const absl::string_view tab_alt; // tab replacement
  +
  + // constructor needed for C++11
  + explicit VisualizeWhitespace(absl::string_view text, char space_alt = '.',
  + absl::string_view newline_alt = "\\\n",
  + absl::string_view tab_alt = "#")
  + : text(text),
  + space_alt(space_alt),
  + newline_alt(newline_alt),
  + tab_alt(tab_alt) {}
  };
  std::ostream& operator<<(std::ostream&, const VisualizeWhitespace& vis);
  