[Feature Request] Bindings for GDI+

[snuk182]

Blocks snuk182/nuklear-rust#1 .

[docbrown]

The GDI+ structures use 8-byte packing, so I don't think this can be implemented until #[repr(packed = "N")] is stabilized (see rust-lang/rust#33158).

[retep998]

@docbrown If the packing is greater than or equal to the struct's natural alignment, then it'll work fine. Only when the packing is lower than the struct's natural alignment, but higher than 1, that is where things are currently impossible.