This MR also contains a few fixes and missing conversions support. We no longer need 32-bit types outside vulkan_thunks.c, so we can default to host struct layouts and use `WINE_VK_HOST` in unixlib. This essentially means that vulkan.c is ready for wow64 (vulkan_thunks.c still needs more patches, mostly applying conversions to more types). Instead of defining *_host types, use local *32 types in generated thunks.