COFF Support

[fosterbrereton]

Adds COFF (Common Object File Format) support to ORC, enabling it to parse and extract DWARF debug information from Windows object files in addition to existing Mach-O support.

New COFF Implementation:

• Created coff.cpp and coff.hpp implementing COFF/PE format parsing (IMAGE_FILE_HEADER, IMAGE_SECTION_HEADER structures)
• Added dwarf_from_coff() to extract DWARF sections from COFF objects
• Detects x64 COFF files via machine type code (0x8664)

Generalized Architecture:

• Renamed macho_params → reader_params and macho_reader_mode → reader_mode throughout codebase
• Updated all file format readers (ar, fat, macho) to use generic params
• Created dwarf_from_object_file() dispatcher that routes to format-specific (COFF/Mach-O) DWARF extractors

DWARF Section Handling:

• Extended section name matching to recognize both Mach-O (__debug_*) and COFF (.debug*) prefixes
• Improved section registration with better error handling (finalized state machine transitions)
• Enhanced freader with leftovers() and templated read<T>() methods

Robustness:

• Added invariant checks for buffer boundaries in freader operations
• Better error reporting for missing DWARF sections
• Handles COFF string table lookups for long section names