merging gtest-port.h, again - 1

googletest/include/gtest/internal/gtest-port.h

@@ -228,10 +228,9 @@
 //
 // Regular expressions:
 //   RE             - a simple regular expression class using the POSIX
-//                    Extended Regular Expression syntax on UNIX-like
-//                    platforms, or a reduced regular exception syntax on
-//                    other platforms, including Windows.
-//
+//                    Extended Regular Expression syntax on UNIX-like platforms
+//                    or a reduced regular exception syntax on other
+//                    platforms, including Windows.
 // Logging:
 //   GTEST_LOG_()   - logs messages at the specified severity level.
 //   LogToStderr()  - directs all log messages to stderr.
@@ -2093,8 +2092,13 @@ class MutexBase {
      extern ::testing::internal::MutexBase mutex
 
 // Defines and statically (i.e. at link time) initializes a static mutex.
+// The initialization list here does not explicitly initialize each field,
+// instead relying on default initialization for the unspecified fields. In
+// particular, the owner_ field (a pthread_t) is not explicitly initialized.
+// This allows initialization to work whether pthread_t is a scalar or struct.
+// The flag -Wmissing-field-initializers must not be specified for this to work.
 #  define GTEST_DEFINE_STATIC_MUTEX_(mutex) \
-     ::testing::internal::MutexBase mutex = { PTHREAD_MUTEX_INITIALIZER, false, pthread_t() }
+     ::testing::internal::MutexBase mutex = { PTHREAD_MUTEX_INITIALIZER, false }
 
 // The Mutex class can only be used for mutexes created at runtime. It
 // shares its API with MutexBase otherwise.