[bug#61240] improve high-res file timestamp in Automake

On 2023-02-03 18:27, Jacob Bachmeyer wrote:
> Where are you actually using a 5.10 feature?

Where lib/Automake/FileUtils.pm says "use Time::HiRes qw(stat);". This 
does not work with Perl 5.6.

For why we bumped the version to 5.10, please see:

https://git.savannah.gnu.org/cgit/autoconf.git/commit/?id=61901a1a14fd50c03cfb1529d091554376fef286

> Please do not arbitrarily bump version requirements just to bump version requirements.

That's not what was done here. The abovementioned URL says version 
requirements were bumped from 5.6 to 5.10 because the feature is not 
present in 5.6 (2000), is present in 5.10 (2007), and we lacked access 
to the museum pieces in the middle. If you are sure that a version 
number lower than 5.10 will do, please let us know.