Clang/mac: Get unit_tests built.

base/logging.h

Index: base/logging.h
diff --git a/base/logging.h b/base/logging.h
index 4d2a6ca0bd0ad926ff75d84dbb73fb016b45d5e4..d8657448118dae1b166b088df9681f88ab171815 100644
--- a/base/logging.h
+++ b/base/logging.h
@@ -114,18 +114,6 @@ inline std::ostream& operator<<(std::ostream& out, const std::wstring& wstr) {
   return out << wstr.c_str();
 }
 
-// XXX better comment -- must be before we use << and in global namespace
-// These functions are provided as a convenience for logging, which is where we
-// use streams (it is against Google style to use streams in other places). It
-// is designed to allow you to emit non-ASCII Unicode strings to the log file,
-// which is normally ASCII. It is relatively slow, so try not to use it for
-// common cases. Non-ASCII characters will be converted to UTF-8 by these
-// operators.
-std::ostream& operator<<(std::ostream& out, const wchar_t* wstr);
-inline std::ostream& operator<<(std::ostream& out, const std::wstring& wstr) {
-  return out << wstr.c_str();
-}
-
 namespace logging {
 
 // Where to record logging output? A flat file and/or system debug log via