[RFC] adding -input and -output options to clang-offload-bundler

Currently, clang-offload-bundler has -inputs and -outputs options that accept values with comma as the delimiter. This causes issues with file paths containing commas, which are valid file paths on Linux.

One solution is to escape comma before passing file names to clang-offload-bundler. However this requests special handling of clang-offload-bundler options in clang and clang-offload-bundler. Also this requires direct clang-offload-bundler users to escape comma.

The second solution is to add two new options -input and -output, which accept one single file, and allow multiple instances. This allows arbitrary file paths. The old -inputs and -outputs options will be kept for backward compatibility, but are not allowed to be used with -input and -output options for simplicity. In the future, -inputs and -outputs options will be phasing out.

I would recommend the second solution.

This affects toolchains using clang-offload-bundler, e.g. HIP, OpenMP.

Your feedback is welcome. Thanks.

@Artem-B @jdoerfert