0.3.0 can't be build on Windows

[cmb69]

From the PECL build logs:

ext\opencensus\opencensus_core_daemonclient.c(335): error C2143: syntax error: missing '{' before '*'

That is because daemonclient is only defined on non Windows platforms (#ifndef PHP_WIN32). If the package is no longer compatible with Windows, please remove config.w32 and add a note in the changelog. Otherwise please fix the build failure.

[MrMage]

I don't have the resources to work on Windows support, but it would probably be great if someone could fix these and add a CI run on Windows.