Merge "Further document MapInfo::elf_offset."

  uint16_t flags = 0;

  std::string name;

  std::shared_ptr<Elf> elf;

  // The offset of the beginning of this mapping to the beginning of the

  // ELF file.

  // elf_offset == offset - elf_start_offset.

  // This value is only non-zero if the offset is non-zero but there is

  // no elf signature found at that offset.

  uint64_t elf_offset = 0;

  // This value is the offset from the map in memory that is the start

  // of the elf. This is not equal to offset when the linker splits

  // This value is the offset into the file of the map in memory that is the

  // start of the elf. This is not equal to offset when the linker splits

  // shared libraries into a read-only and read-execute map.

  uint64_t elf_start_offset = 0;