Thread safety of any.h

[newstzpz]

The following code in https://github.com/mariusmuja/flann/blob/master/src/cpp/flann/util/any.h is not thread safe in MSVC until VS 2015 ("Magic statics" support in https://msdn.microsoft.com/en-us/library/hh567368.aspx). This may crash the program randomly when creating multiple Index objects (KDTreeSingleIndex etc.) at the same time.

/// This function will return a different policy for each type. template<typename T> base_any_policy* get_policy() { static typename choose_policy<T>::type policy; return &policy; }

[victl]

In case any one also run into this issue, I found the solution to be this one