epub generation depends on perl Archive::ZIP module

[Patrice Dumas]

Hello,

Creating the final epub file requires the perl Archive::Zip module.
If the customization variable EPUB_CREATE_CONTAINER_FILE is set to 0,
this step is not performed, this is used in the tests.

What should we do for that dependence?  I don't have a good idea.
Detecting at configure time and passing the information could be done
but would require quite a bit of coding and does not fix the issue
correctly, in my opinion, as what matters is the presence at
runtime.

Leaving things as they are now, there is an error mesage like that,
which is not very user friendly:

./texi2any.pl --epub3 test_config.texi 
Can't locate Archive/Zip.pm in @INC (you may need to install the Archive::Zip 
module) (@INC contains: ../tp/maintain/lib/Text-Unidecode/lib 
../tp/maintain/lib/Unicode-EastAsianWidth/lib 
../tp/maintain/lib/libintl-perl/lib ../tp/Texinfo/XS/parsetexi ../tp/Texinfo/XS 
../tp . /home/dumas/perl5/lib/perl5//5.34.0/x86_64-linux-gnu-thread-multi 
/home/dumas/perl5/lib/perl5//5.34.0 
/home/dumas/perl5/lib/perl5//x86_64-linux-gnu-thread-multi 
/home/dumas/perl5/lib/perl5/ 
/home/dumas/src/mini_ker_install/share/perl/5.32.1/ /etc/perl 
/usr/local/lib/x86_64-linux-gnu/perl/5.34.0 /usr/local/share/perl/5.34.0 
/usr/lib/x86_64-linux-gnu/perl5/5.34 /usr/share/perl5 
/usr/lib/x86_64-linux-gnu/perl-base /usr/lib/x86_64-linux-gnu/perl/5.34 
/usr/share/perl/5.34 /usr/local/lib/site_perl) at ../tp/ext/epub3.pm line 714.

Any idea?  There is probably a way to use an eval block or something
that tests that the require Archive::Zip works and another message can
be used instead, but I am not sure that it is really so much better.

-- 
Pat