bpo-40268: Remove unused structmember.h includes (GH-19530)
If only offsetof() is needed: include stddef.h instead.
When structmember.h is used, add a comment explaining that
PyMemberDef is used.
diff --git a/Parser/asdl_c.py b/Parser/asdl_c.py
index bd22fb6..c98f949 100755
--- a/Parser/asdl_c.py
+++ b/Parser/asdl_c.py
@@ -1428,7 +1428,7 @@
f.write('\n')
f.write('#include "Python.h"\n')
f.write('#include "%s-ast.h"\n' % mod.name)
- f.write('#include "structmember.h"\n')
+ f.write('#include "structmember.h" // PyMemberDef\n')
f.write('\n')
generate_module_def(f, mod)