Make code compile on clang again

There are a couple places we missed inline/static on our headers, and a
couple unused message entry callbacks for which their parameters were
incorrect (which clang caught).  Fix all of them.

Tested: Code compiles on clang.  No-op changes.

Signed-off-by: Ed Tanous <edtanous@google.com>
Change-Id: I12c9c04d3b773c4991c6cd92d0cfd42b348762d6