Don't use abi_only items in the headers check

Tools/scripts/stable_abi.py

@@ -304,13 +304,21 @@ def do_unixy_check(manifest, args):
  manifest, LDLIBRARY, expected_symbols, dynamic=False)
 
  # Check definitions in the header files
+ expected_defs = set(item.name for item in manifest.select(
+ {'function', 'data'}, include_abi_only=False, ifdef=feature_defines,
+ ))
  found_defs = gcc_get_limited_api_definitions(['Include/Python.h'])
- missing_defs = expected_symbols - found_defs
+ missing_defs = expected_defs - found_defs
  okay &= _report_unexpected_items(
  missing_defs,
  'Some expected declarations were not declared in '
  + '"Include/Python.h" with Py_LIMITED_API:')
- extra_defs = found_defs - expected_symbols
+
+ # Some Limited API macros are defined in terms of private symbols.
+ # These are not part of Limited API (even though they're defined with
+ # Py_LIMITED_API). They must be part of the Stable ABI, though.
+ private_symbols = {n for n in expected_symbols if n.startswith('_')}
+ extra_defs = found_defs - expected_defs - private_symbols
  okay &= _report_unexpected_items(
  extra_defs,
  'Some extra declarations were found in "Include/Python.h" '