Consider adding native library folders to the process DLL search path

[glopesdev]

Starting from Windows 8 and Windows 7 SP1 KB2533623, Microsoft introduced new API enhancements for securely loading external native libraries.

These API calls define a process wide DLL search path which can be modified only by direct calls to these OS-specific functions. Some modern libraries specify the DefaultDllImportSearchPath attribute set to DllImportSearchPath.SafeDirectories which means that only this process wide DLL search path is used for loading native libraries, and the directories under the default PATH environment variable are ignored.

To workaround this, the bootstrapper should call the AddDllDirectory method for each active native library folder when bootstrapping the environment.

Unfortunately, adding the same folders to the PATH environment variable is still required, as the new process wide DLL search path is not used by some legacy libraries.