fflush() on readonly files

[Radim Kolar]

I have submitted pr http://www.freebsd.org/cgi/query-pr.cgi?pr=65402 with patch
which makes fflush() on read only descriptors do not return error code.

Reasons for this patch:
1 - Do not breaks ISO C standard
2 - Makes FreeBSD undefined behavior compatible with other operation systems
3 - Correct some programs depending on this
4 - Makes fflush() and fsync() behavior identical - avoids programmer's confusion.
5 - If there are no data to flush() then flush operation (dummy) succeeds, not failed.

Against this patch:
  Programs which rely upon fflush() not returning an error
  when passed a file which is opened read-only are broken,
  and should be fixed.

  Colin Percival

Are there any other reasons for non commiting it? I think that in this case
pro > cons.