cygwin: Handle differences in the XDR implementation

cygwin: Handle differences in the XDR implementation

Cygwin's XDR implementation defines xdr_u_int64_t instead of
xdr_uint64_t and lacks IXDR_PUT_INT32/IXDR_GET_INT32.

Alter the IXDR_GET_LONG regex in rpcgen_fix.pl so it doesn't destroy
the #define IXDR_GET_INT32 IXDR_GET_LONG in remote_protocol.x.

Also fix the remote_protocol.h regex in rpcgen_fix.pl.