Typedefs starting with `i' in Quake

• IN_ADDR Quake/mpdosock.h:773
• IoctlArgs Quake/mplpc.c:80
• IPXaddr Quake/net_ipx.c:60
• IPXheader Quake/net_ipx.c:78
• ipx_lowmem_buffer_t Quake/net_ipx.c:105