Provide a C shared lib build options

[noandrea]

• I'm submitting a ...

  • bug report
  • feature request
  • support request => Please do not submit support request here, see note at the top of this template.

• What is the expected behavior?

provide a c shared library that can be used in other languages (rust, c, c++, py ...)

• What is the motivation / use case for changing the behavior?

Golang has the builtin ability to produce c shared libraries, it would be great to have it included and tested in the current go library

• Other information (e.g. detailed explanation, stacktraces, related issues, suggestions how to fix, links for us to have context, eg. forum, telegram, etc)

some references articles are:
https://medium.com/learning-the-go-programming-language/calling-go-functions-from-other-languages-4c7d8bcc69bf#.n73as5d6d

https://github.com/vladimirvivien/go-cshared-examples

[noandrea]

also provide an example / how to with C++