Use ptrdiff_t for struct_member_t.offset, etc

We have several fields in our configuration code that use int for a struct offset:

  • struct_member_t.offset
  • struct_magic_decl_t.magic_offset
  • config_format_t.config_suite_offset

These should all use ptrdiff_t instead.

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information