I think the right thresholds are 5.10 for absolute minimum and 5.16
for 'we aren't going to test with anything older than this'
I appreciate the effort to increase compatibility with old versions.
I imagine you could provide Digest::SHA "internally", or test for it as
Nick suggested, but I know how much of a pain it is to avoid/check for
use of things that have seemingly been around forever. (Comes up all the
time in the TeX world.)
_Possibly_ we would also want `use open qw(:std :utf8)`, I'm not sure.
I feel sure that people have old-but-working Autoconf-related files in
other encodings. What would be gained by forcing UTF-8?
For that matter, I'm not sure why Autoconf (or Automake) needs to be
Unicode-aware at all?
Best,
Karl
