11877.5.diff incorporates all changes suggested by
Charles-François except for the 'auto' keyword, which is extremely
important and which would need to be invented if it would not
yet exist.

I'm dropping the old stuff.  And i think this is the final version
of the patch.  I've changed the default argument to 'True' as
i really think it's better to be on the safe side here.  (The
french are better off doing some gracy and dangerous sports to
discover edges of life!)  I'm still of the opinion that this
should be completely hidden, but since it's completely transparent
wether a Python function gets yet another named argument or not...

So, thanks to Ronald, i detected that also NetBSD introduced
a FDISKSYNC flag in 2005 and that you really need fsync_range()
there (at least by definition)!  How could they do that?  But i'm
also happy to see that all other systems try hard to achieve
security transparently and by default and unless i missed
something once again.