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This adds a hard dependency on one of Botan or gcrypt. Botan is already a
recommended dependency, and gcrypt is probably packaged almost everywhere,
so this should not be a big deal.

ref #3241

And add a test for it.

fix #3238

This reverts commit 26eb28dc.

[ci skip]

fix #3235

fix #2694 (yeah, it was closed, but it was badly fixed)

ref #3231

fix #3231

fix #3231

To correctly exit the process

We don’t need any UTF-8 support here, and it’s more portable