Otherwise the colon confuses make on Windows

The : in c:/foo/bar on Windows confuses make.

I've sent them upstream here:
    https://sourceforge.net/tracker/?func=detail&aid=3484051&group_id=163236&atid=826945

I'll send them to pretty upstream.

I've sent them to the upstream bytestring bug report addresses

On OS X, /tmp is a symlink to /private/tmp, so the test prints the wrong
output. I've changed it to use /dev instead, which is hopefully less
likely to be a symlink.

It was explicitly removing the program inbetween the two runs, but
I don't see why that should be necessary.

We now just sleep for 2 seconds, rather than using
    touch --date="now + 3 seconds"
which doesn't work on OS X. OS X does have "touch -A", but that doesn't
work on Linux.