constexpr defaulted default constructor of WrappedMutex causes compile errors

[przole]

Version: 3.15.8
Language: C++

Windows 10 Enterprise 20H2 19042.867

Microsoft Visual Studio Enterprise 2019 Version 16.9.4

Steps to reproduce the behavior:

1. Compile project with generated protobuf class causes:

Error defaulted default constructor cannot be constexpr because the corresponding implicitly declared default constructor would not be constexpr ...\include\google\protobuf\stubs\mutex.h 119

constexpr WrappedMutex() = default;
should be:
constexpr WrappedMutex() {}

[elharo]

fixed, I think