Over enforced naming in shared library name?

While using bindgen against a library with a name such as '-1.0.0', bindgen generates " is not a valid Ident". This seems overly restrictive given that many libraries use such conventions. Renaming to '_1.0.0' also produces the same issue as '.' is not allowed in the name. Bindgen seems to be forcing a validation of the name against Rust "Ident" which is severely limiting when used against common library naming practices. I would expect that the name of the shared library should allow arbitrary conventions without this limit as the generated code does not seem to reference the name in any notable manner, at least with the settings I'm using.

Start by reproducing the issue with bindgen against a shared library named '-1.0.0' and '_1.0.0', then trace where the library name is validated as a Rust identifier. Done means conventional shared-library names no longer trigger the invalid-identifier error when they are not used as generated Rust identifiers; add a regression test for these names.