An XDR integer is a 32-bit data item that encodes a C integer. It is represented
in twos complement notation, with the most significant byte of the
C integer in the first byte of the XDR integer and the least significant byte
of the C integer in the fourth byte of the XDR integer. That is, XDR uses
big-endian format for integers. XDR supports both signed and unsigned
integers, just as C does.