[PATCH] Proper whole-archive handling

[Joerg Sonnenberger]

  The problematic part for the using buffer and path from the LinkerInput is the handling of archives. For those it is required to create a new LinkerInput with a different (derived) buffer and optionally, a different path. If that is desirable, LinkerInput should move into Core, currently it is part of Driver.

http://llvm-reviews.chandlerc.com/D1587