stubs/mutex: Fix compilation by initializing variable in WrappedMutex class.
This solves the following error in gcc:
explicitly defaulted function cannot be declared 'constexpr' because the implicit declaration is not 'constexpr'
diff --git a/src/google/protobuf/stubs/mutex.h b/src/google/protobuf/stubs/mutex.h
index 64c4d6a..5c16c7e 100644
--- a/src/google/protobuf/stubs/mutex.h
+++ b/src/google/protobuf/stubs/mutex.h
@@ -124,12 +124,12 @@
void AssertHeld() const {}
private:
-#if defined(_MSC_VER)
- CallOnceInitializedMutex<std::mutex> mu_;
-#elif defined(GOOGLE_PROTOBUF_SUPPORT_WINDOWS_XP)
- CallOnceInitializedMutex<CriticalSectionLock> mu_;
+#if defined(GOOGLE_PROTOBUF_SUPPORT_WINDOWS_XP)
+ CallOnceInitializedMutex<CriticalSectionLock> mu_ {};
+#elif defined(_MSC_VER)
+ CallOnceInitializedMutex<std::mutex> mu_ {};
#else
- std::mutex mu_;
+ std::mutex mu_ {};
#endif
};
