Here are some ISO C conformance patches, and
a minor cleanup I encountered along the way.

Lib/distutils/tests/test_config_cmd.py // comment --> /* comment */.
Lib/distutils/tests/test_build_ext.py,
Objects/weakrefobject.c,
Modules/_pickle.c,
Modules/_testcapimodule.c,
Python/import.c  .  .  .  .  .  .  .   Remove some invalid ',' and ';'s.
Python/Python-ast.c,
Modules/arraymodule.c  .  .  .  .  .   Non-constant array initializer.
Modules/_csv.c   .  .  .  .  .  .  .   Slight cleanup.
Modules/_ctypes/libffi/src/x86/ffi.c   Empty translation unit.

TODO when bored, if anyone cares for more pedantic ISO patches:
- printf(%p, non-void* pointer): The pointer should be cast to void*.
- More // comments -> /**/, but mostly in system-specific code so I
  can't test any patches I make.