Add first up to 8 character of used hedaer.b into AR

prevent dkim_ar_cat from lose last character It losed the last character when the length resulted string was multiple of 256

Never swallow an email with malformed AR header

Avoid implicit = in AR parser

Simplified parser of AR header which should improve it's stability on edge cases as well.

Improve serialization of AR header Here two fixes: (1) avoid loop when checkpoint starts from whitespace, and (2) avoid infintity loop on very long last field.

Fix memory leak

Never use duplicated header multiple times

Revert previous. It's too early to remove the guards just yet.

Remove HAVE_ED25519 now that we have ED25519 in LibreSSL

Handle spaces in key-p-tag correctly. Reported by Mischa Peters.

opensmtpd.h should be taken from standard include path

Remove assert. Shouldn't be in production code

Put pklen and tmp in #ifdef HAVE_ED25519

pkrawlen should only be used to test the length, not if the tag might be there or not

Apparently I broke RSA in previous commit

Add support for ed25519

Domains are case insensitive. Keep that in mind when comparing i- and d-tag

osmtpd_ltok_skip_sig_h_tag_value can be further out than end, because a header can contain a ';'

FWS after h=-tag value could lead to a end mismatch. Use osmtpd_ltok_skip_sig_h_tag_value for checking and original code for copying data

Use osmtpd_ltok_skip_sig_i_tag_value() instead of parsing it manually where not needed

osmtpd_ltok_skip_domain has obs-domain, which gives the wrong result. Use the appropriate osmtpd_ltok_skip_sig_d_tag_value

signature pkey also needs to be freed after we're done with it.

Move ar_data free to the end of the fuction, so that failed queries also get released

Free ar_data, as suggested by asr_run(3)