O_TEMPORARY OPTION (FILE NOT REMOVED)

The problem was that O_TEMPORARY is only defined on Windows and
not on any of our other supported platforms. This flag is used
to indicate that a file is temporary and should be deleted
automatically. On other platforms it was #defined to 0 and thus
had no effect. This mean that special handling was needed
everywhere O_TEMPORARY was used.

This patch fixes the problem by removing O_TEMPORARY (instead
of introducing a new flag which might conflict with existing
OS flags). Cleanup of temporary files is now done with common
code on all platforms.

The patch also removes O_SHARE and O_SHORT_LIVED which was
not supported on any platforms (and thus #defined to 0).
It also removes O_BINARY. It was only defined on Windows
and my_win_open() always adds _O_BINARY anyway.