[Bug-tar] Differential \\ incremental tar archives and CTIME time stamp problem

[x y]

Hello,

Windows Explorer is updating the CTIME time stamp of files even if the
contents are not modified. While doing differential \ incremental tar
archives under Cygwin, this becomes a problem as unmodified files are
introduced to the tar archive. For example, opening and closing a MS
Office document or opening and closing a text file with notepad
updates CTIME. This happens even if the files are not modified.

Here is how to reproduce the issue :

During a Cygwin session, let's create a simple text file :

$ echo 123 > testfile.txt

address@hidden ~
$ stat testfile.txt
  File: 'testfile.txt'
  Size: 4               Blocks: 1          IO Block: 65536  regular file
Device: bc73cfd9h/3161706457d   Inode: 4503599627418701  Links: 1
Access: (0644/-rw-r--r--)  Uid: (197108/Administrator)   Gid: (197121/    None)
Access: 2016-05-26 23:34:14.437500000 +0300
Modify: 2016-05-26 23:34:14.437500000 +0300
Change: 2016-05-26 23:34:14.437500000 +0300
 Birth: 2016-05-26 23:34:14.437500000 +0300

One minute later, opening and closing testfile.txt with notepad and
checking the time stamps. The content of the text file is not modified
:

address@hidden ~
$ stat testfile.txt
  File: 'testfile.txt'
  Size: 4               Blocks: 1          IO Block: 65536  regular file
Device: bc73cfd9h/3161706457d   Inode: 4503599627418701  Links: 1
Access: (0644/-rw-r--r--)  Uid: (197108/Administrator)   Gid: (197121/    None)
Access: 2016-05-26 23:35:36.953125000 +0300
Modify: 2016-05-26 23:34:14.437500000 +0300
Change: 2016-05-26 23:35:35.156250000 +0300
 Birth: 2016-05-26 23:34:14.437500000 +0300

CTIME ( Change ) is updated. tar will add again this file to the next
incremental \ differential archive because both CTIME and MTIME are
checked by tar.

Kindly, could it be possible to add a new option to tar to ignore
CTIME on demand while creating
incremental \ differential archives? The implementation of this option
can be probably reflected
to Cygwin and the problem can be solved.