The --import-debug-info CLI flag and the ImporterOptions::
AdditionalDebugInfoPaths field it populated were a side-channel that
loaded extra DWARF files outside the normal ELF dependency-resolution
path. It bypassed the symbol-aware machinery and is no longer needed.
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.
Fix the behavior of binary importers by propagating the path of the
input binary from revng2 downwards, allowing finding `.debug` files in
the correct paths.
Replace the stub implementation of invalidation with the proper
implementation. A ReadPathCache is added to each global so that it can
keep tracks of what target are associated to which read paths.
Alessandro Di Federico