https://github.com/xmos/xscope_fileio/blob/master/xscope_fileio/api/xscope_io_device.h#L75
vs
#include <stdio.h>
size_t fwrite(const void *buf, size_t size, size_t count, FILE *fp);
Looks like this was fixed earlier on @ v0.2.0 but somehow this issue got re-introduced.
This would be a breaking change so need to bump major version number (we are probably ready for v1.0.0 anyhow)