This patch adds anonymous namespaces support to the native PDB plugin.
I had to reference from the main function variables of the types that are inside of the anonymous namespace to include them in debug info. Without the references they are not included. I think it's because they are static, then are visible only in the current translation unit, so they are not needed without any references to them.
There is also the problem case with variables of types that are nested in template structs. For now I've left FIXME in the test because this case is not related to the change.