This adds a mechanism so `bindgen` is able to run `Bindings::generate`
multiple times with the same user input if the `generate_static_inline`
option is enabled and `GenerateError::ShouldRestart` is returned by
`Bindings::generate`.

This is done to eventually solve rust-lang#1090 which would require to check for
any static inline functions and generate a new header file to be used as
an extra input and run `Bindings::generate` again.