wrong atime and mtime in file config.h.in created using autoheader in a bind-mounted directory

[Alejandro Pinio]

1) ❯ lsb_release -rd
Description: Ubuntu 18.04.4 LTS
Release: 18.04

2) ❯ apt-cache policy autoconf
autoconf:
  Installed: 2.69-11
  Candidate: 2.69-11
  Version table:
 *** 2.69-11 500
        500 http://ar.archive.ubuntu.com/ubuntu bionic/main amd64 Packages
        500 http://ar.archive.ubuntu.com/ubuntu bionic/main i386 Packages
        100 /var/lib/dpkg/status

3) expected behavior: atime and mtime of file config.h.in file created using autoheader in a bind-mounted directory are representative of the time at which the file was created

4) actual behavior: atime and mtime of file config.h.in file created using autoheader in a bind-mounted directory are rounded to the second

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Steps to reproduce the bug (check for relevant information in other issue comments): https://github.com/docker/for-linux/issues/990#issuecomment-620538818