Fix the compilation issue on the Windows platform.

[CapricornFBQ]

1. Fix the compilation issue on the Windows platform by include parts of the standard library.
2. Fix the issue where exporting the "defaultClockRate" static variable in datachannel.lib/dll fails on the Windows platform.

[paullouisageneau]

Please don't change submodules, currently the build is broken as a result.

The library builds fine with MSVC, what is your setup?

2. Fix the issue where exporting the "defaultClockRate" static variable in datachannel.lib/dll fails on the Windows platform.

What is the problem exactly and why would Windows require special treatment? Static variables must be inline, otherwise it's just a declaration and there must be a definition outside the class, that's why you hit "undefined reference" errors at first.

[CapricornFBQ]

I apologize for not providing the context for the issue initially. I am using Visual Studio 2017 with SDK version 10.0.17763.0 and compiler version 19.16.27051. When I compile examples/streamer, there is an issue where defaultClockRate is not defined. After troubleshooting, I found that the ”datachannel.dll“ did not export this variable. It appears that on the Windows platform, there is a conflict when using inline and __declspec(dllexport) together.

[paullouisageneau]

I'd be OK to fix the includes but the issue with inline and __declspec(dllexport) seems to be an issue with Visual Studio 2017. Again, the library builds fine on Windows with Visual Studio 2022 and MSVC 19.39.33523.0. Have you tried with a more recent version?

[paullouisageneau]

Closing in favor of #1280