generate_pod(type) not working on std::is_pod(type)

[MidasLamb]

Describe the bug
I have a C++ type that is a pod (with static_assert(!std::is_pod) it fails, notice the !)

cargo:warning=src/bindings/osr/client_osr.cc:375:15: error: static assertion failed
cargo:warning=  375 | static_assert(!std::is_pod<cef_rect_t>());

so that means that cef_rect_t is a pod (according to the c++ function), but calling generate_pod("cef_rect_t") fails with

called `Result::unwrap()` on an `Err` value: ParseError(AutocxxCodegenError(Conversion(Cpp(UnsafePodType("Type cef_rect_t is a typedef to a complex type")))))

cef_rect_t is defined as follows:

typedef struct _cef_rect_t {
  int x;
  int y;
  int width;
  int height;
} cef_rect_t;

If I specify generate_pod("_cef_rect_t") (notice the leading underscore), then the generated cef_rect_t will also be marked as Trivial, but I still cannot specify generate_pod("cef_rect_t"), only generate("cef_rect_t"). The problem is mainly that other structs that contain a cef_rect_t that cannot be marked as a POD because of this.

Expected behavior
When static_assert(std::is_pod<cef_rect_t>()) passes, I should be able to use generate_pod("cef_rect_t")

[adetaylor]

Please raise a PR test case