[PATCH v1] handle warnings when application is compiled with -Wconversion or -Wpacked

[JereLeppanen]

This series avoids or ignores warnings from ODP headers and ODP helper headers when application is compiled with -Wconversion or -Wpacked.

For -Wpacked, there are at least four different options, in order of increasingly fine granularity:

1. Don't do anything, let the application handle it.
2. Ignore the warnings in all helper headers. (v1)
3. Ignore the warnings in the affected helper headers.
4. Ignore the warnings for the affected structs,