gh-131238: Add explicit includes to pycore headers (#131257)

Python/symtable.c

@@ -2,7 +2,12 @@
 #include "pycore_ast.h"           // stmt_ty
 #include "pycore_parser.h"        // _PyParser_ASTFromString()
 #include "pycore_pystate.h"       // _PyThreadState_GET()
+#include "pycore_runtime.h"       // _Py_ID()
 #include "pycore_symtable.h"      // PySTEntryObject
+#include "pycore_unicodeobject.h" // _PyUnicode_EqualToASCIIString()
+
+#include <stddef.h>               // offsetof()
+
 
 // Set this to 1 to dump all symtables to stdout for debugging
 #define _PY_DUMP_SYMTABLE 0