Determine the existence of hash_map/hash_set in gtest-port.h.

include/gtest/internal/gtest-port.h

@@ -606,6 +606,15 @@ struct _RTL_CRITICAL_SECTION;
 # include <time.h>  // NOLINT
 #endif
 
+// Determines if hash_map/hash_set are available.
+// Only used for testing against those containers.
+#if !defined(GTEST_HAS_HASH_MAP_)
+# if _MSC_VER
+#  define GTEST_HAS_HASH_MAP_ 1  // Indicates that hash_map is available.
+#  define GTEST_HAS_HASH_SET_ 1  // Indicates that hash_set is available.
+# endif  // _MSC_VER
+#endif  // !defined(GTEST_HAS_HASH_MAP_)
+
 // Determines whether Google Test can use tr1/tuple.  You can define
 // this macro to 0 to prevent Google Test from using tuple (any
 // feature depending on tuple with be disabled in this mode).

src/gtest-port.cc

@@ -887,7 +887,6 @@ GTEST_API_ ::std::string FormatCompilerIndependentFileLocation(
     return file_name + ":" + StreamableToString(line);
 }
 
-
 GTestLog::GTestLog(GTestLogSeverity severity, const char* file, int line)
     : severity_(severity) {
   const char* const marker =

test/gtest-printers_test.cc

@@ -50,13 +50,13 @@
 
 #include "gtest/gtest.h"
 
-// hash_map and hash_set are available under Visual C++.
-#if _MSC_VER
-# define GTEST_HAS_HASH_MAP_ 1  // Indicates that hash_map is available.
+// hash_map and hash_set are available under Visual C++, or on Linux.
+#if GTEST_HAS_HASH_MAP_
 # include <hash_map>            // NOLINT
-# define GTEST_HAS_HASH_SET_ 1  // Indicates that hash_set is available.
+#endif  // GTEST_HAS_HASH_MAP_
+#if GTEST_HAS_HASH_SET_
 # include <hash_set>            // NOLINT
-#endif  // GTEST_OS_WINDOWS
+#endif  // GTEST_HAS_HASH_SET_
 
 #if GTEST_HAS_STD_FORWARD_LIST_
 # include <forward_list> // NOLINT