Refactor the binary import and dependency resolution infrastructure to
support multiple platforms (Linux, Windows, macOS) via a
configuration-driven root system.
Major changes:
* Overhaul PDB and DWARF importers for platform-aware debug info
loading.
* Refactor LDDTree into a template-based architecture with
platform-specific implementations (ELF, PE/COFF).
* Mostly rewrite the PDB importer, which had significant limitations.
Alessandro Di Federico
09dfccec91