support for non-standard types

[mbroadst]

Hi, I'm using your module to support communication with libvirt using their remote protocol XDR definition and running into issues with their definition. They use types which aren't defined in the spec itself, however are supported by rpcgen - specifically: unsigned char, char, unsigned short, and short (widths of 1 and 2 respectively). I thought they were doing some sort of custom trickery, but it turns out these are indeed supported by libxdr (e.g. https://linux.die.net/man/3/xdr_u_char).

It looks like at least in the case of char's this is a very inefficient representation of characters, where you could otherwise store it as an opaque and not incur the padding overhead, but alas its supported. Would you have any interest in adding support for these types to your module?

Thanks.