See #1007744

Currently building on hppa fails with:

    test-backtrace.c:10: Assert failed: backtrace_append(bt) == 0
    test-backtrace.c:14: Assert failed: strstr(str_c(bt), "test_backtrace") != NULL
    backtrace_append ..................................................... : FAILED
    test-backtrace.c:34: Assert failed: backtrace_get(&bt) == 0

on riscv64:

    Debug: backtrace: './test-lib(+0x734d8) [0x2aaab1d4d8]'
    test-backtrace.c:21: Assert failed: strstr(str_c(bt), "test_backtrace_append") != NULL || strstr(str_c(bt), "main") != NULL
    backtrace_append ..................................................... : FAILED
    Debug: backtrace: './test-lib(+0x734d8) [0x2aaab1d4d8]'
    test-backtrace.c:45: Assert failed: strstr(bt, "test_backtrace_get") != NULL || strstr(bt, "main") != NULL
    backtrace_get ........................................................ : FAILED

on sparc64:

    Debug: backtrace: './test-lib(+0x95ec8) [0x10000095ec8]'
    test-backtrace.c:21: Assert failed: strstr(str_c(bt), "test_backtrace_append") != NULL || strstr(str_c(bt), "main") != NULL
    backtrace_append ..................................................... : FAILED
    Debug: backtrace: './test-lib(+0x95ec8) [0x10000095ec8]'
    test-backtrace.c:45: Assert failed: strstr(bt, "test_backtrace_get") != NULL || strstr(bt, "main") != NULL
    backtrace_get ........................................................ : FAILED

Update to upstream version '2.3.19+dfsg1'
with Debian dir 2d22e19edc94269b79ac43c9185b194ae9a53365

Debian does not support skipping stable releases.
Also drop outdated comment.

* Drop legacy backticks in favor of $(...)
* Quote filenames to prevent globbing and word splitting
* Use /run instead of legacy /var/run

Debhelper generates the following automatically:

    # Automatically added by dh_installsystemd/13.7.1
    if [ -z "${DPKG_ROOT:-}" ] && [ "$1" = remove ] && [ -d /run/systemd/system ] ; then
	    deb-systemd-invoke stop 'dovecot.socket' >/dev/null || true
    fi

Drop the following patches, which are included in this upstream
release:

mail-cache-bigendian-1.patch
login-proxy-Fix-potential-memory-leak-if-backend-login-fa.patch
plugins-imapsieve-imap-sieve-storage-Make-sure-mail_set_u.patch

Update to upstream version '2.3.18+dfsg1'
with Debian dir 67973fff18b27ebe8471fc587556cec761041115

Gbp-Dch: Ignore

Package 2.3.17.1

See merge request !25

W: dovecot-core: debian-changelog-line-too-long line 8

W: dovecot-imapd: mismatched-override hardening-no-fortify-functions usr/lib/dovecot/imap
I: dovecot-imapd: hardening-no-fortify-functions [usr/lib/dovecot/imap]

W: dovecot-core: mismatched-override bash-term-in-posix-shell [etc/init.d/dovecot:43] '| ulimit'
I: dovecot-core: bash-term-in-posix-shell '| ulimit' [etc/init.d/dovecot:43]

P: dovecot source: update-debian-copyright 2018 vs 2021 [debian/copyright:101]

See https://dovecot.org/list/dovecot/2021-September/123057.html

Enhance backtraces on architectures where libunwind is supported.

Lua 5.3 is EOL, see https://www.lua.org/versions.html

- skip arm64 cross build due to epoll checks via AC_TRY_RUN

- do not fail on Lintian warnings due to groff-message, see #973313 and
  salsa-ci-team/pipeline#182