Incompatibility with libloading 0.9.0

Hi all,

When I use bindgen with libloading, starting from 0.9.0, there is an issue with a trait requirement inside a new method.

    |         let library = ::libloading::Library::new(path)?;
    |                       -------------------------- ^^^^ the trait `AsFilename` is not implemented for `P`
    |                       |
    |                       required by a bound introduced by this call
    |
note: required by a bound in `libloading::Library::new`
   --> ***\libloading-0.9.0\src\safe.rs:84:38
    |
    |     pub unsafe fn new(filename: impl AsFilename) -> Result<Library, Error> {
    |                                      ^^^^^^^^^^ required by this bound in `Library::new`
help: consider further restricting type parameter `P` with trait `AsFilename`
    |
    |         P: AsRef<::std::ffi::OsStr> + libloading::AsFilename,
    |                                     ++++++++++++++++++++++++

Start by reproducing the bindgen use case with libloading 0.9.0 and inspect the code around the Library::new call and its generic path parameter. Done means the affected bindgen usage compiles successfully with libloading 0.9.0 without requiring an incompatible trait bound.