Revert "_object: filter non-external symbols in dylibs (#16)"

This reverts commit 2b72105.

abi3audit/_object.py

@@ -155,13 +155,17 @@ def __iter__(self) -> Iterator[Symbol]:
                 raise SharedObjectError("shared object has no symbol table")
 
             for symbol in symtab_cmd.symbols:
-                # We only care about symbols that have the external bit set,
-                # since these are the ones resolved when linking to CPython.
-                if not symbol.type & 0x01:
+                # TODO(ww): Do a better job of filtering here.
+                # The Mach-O symbol table includes all kinds of junk, including
+                # symbolic entries for debuggers. We should exclude all of
+                # these non-function/data entries, as well as any symbols
+                # that isn't marked as external (since we're linking against
+                # the Python interpreter for the ABI).
+                if (name := symbol.name) is None:
                     continue
 
                 # All symbols on macOS are prefixed with _; remove it.
-                yield Symbol(symbol.name[1:])
+                yield Symbol(name[1:])
 
 
 class _Dll(_SharedObjectBase):