rdiff runs with: IO error on fedora

[bigplum]

$ uname -a
Linux localhost.localdomain 3.9.2-200.fc18.x86_64 #1 SMP Mon May 13 13:59:47 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux

$ ./rdiff signature buf.c s.out
rdiff: ERROR: IO error

I found that the IO error was returned by rs_outfilebuf_drain()

present = buf->next_out - fb->buf;
if (present > 0) {
    int result;

    assert(present > 0);

    result = present < (f->len - f->fptr) ? present : (f->len - f->fptr);
    memcpy(f->src + f->fptr, fb->buf, result);
    f->fptr += result;
    if (present != result) {
        return RS_IO_ERROR;
    }

[redserpent7]

have the same issue for Windows