Fix texinfo 7 dependency on perl

Texinfo 7 depends on perl.
If one does not have perl installed, the following error is raised:

```
INFO checking for perl... /usr/bin/perl
INFO checking Perl version and modules... no
INFO configure: error: perl >= 5.8.1 with Encode and Data::Dumper required by Texinfo.
```

See merge request !1728
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