Ability to pass load library flags on Windows

We have a use case where flags like LOAD_LIBRARY_SEARCH_DLL_LOAD_DIR | LOAD_LIBRARY_SEARCH_SYSTEM32 needs to be passed to dlopen for CFFI to successfully load the DLL due to dependencies. This is not possible to do with LoadLibrary and requires LoadLibraryEx. Currently it looks like CFFI is swallowing any flags passed.

This is related to using CFFI in ABI-mode.