changelog: use "vfs.fstat()" instead of "util.fstat()"...
changelog: use "vfs.fstat()" instead of "util.fstat()"
Just invoking "os.fstat()" with "file.fileno()" doesn't require non
ANSI file API, because filename is not used for invocation of
"os.fstat()".
But "util.fstat()" should invoke "os.stat()" with "fp.name", if file
object doesn't have "fileno()" method for portability, and "fp.name"
may cause invocation of non ANSI file API.
So, this patch makes the constructor of appender class invoke
"util.fstat()" via vfs, to encapsulate filename handling.