exim: update to 4.100

exim: update to 4.100

Security release, plus one further release the same day.

4.99.5:
JH/01 Restrict named-queue names. Previously, files could be corrupted by
      poor choices of name. (GCVE-25-2026-07-45-1)

JH/02 Do not expand a local_part gotten from a .forward file, under
      force_command in a pipe transport. (GCVE-25-2026-07-45-3)

4.100: fixes a use-after-free in duplicate processing combined with
continued transport; fixes crashes after deferred local deliveries
from an uninitialised pointer, and excessive DNS lookups on temporary
errors for remote deliveries, both from a mistaken 4.99 optimisation;
fixes a memory leak in DNS lookups present since 4.95; fixes
Proxy-protocol connections evaluating host-based ACL options
(host_reject_connection, helo_verify_hosts, message_size_limit, and
others) against the proxy's own address/name instead of the real
client behind it. Also: dbm lookups no longer return tainted data by
mistake, RFC2047-encoding header size counting, DMARC for empty
envelope senders, and a number of smaller build/portability fixes.

Refreshed patches/030-openssl-deprecated.patch,
patches/100-localscan_dlopen.patch and patches/200-fix-build.patch
for context moved by the version bump. patches/100 also needed six
log_write() call sites fixed: 4.100 dropped log_write()'s leading
selector argument, so the patch's dlopen-failure diagnostics were
passing LOG_MAIN|LOG_REJECT into the format-string slot. All four
patches, including 050, now carry git am headers.

Extended patches/050-fix-crosscompile.patch: 4.100 fixed the dkim.o
partial-link rule in src/miscmods/Makefile (raw `ld -r` -> `$(LD) -r`)
but left the sibling dmarc.o/dmarc_native.o and sieve_filter.o rules
on the unqualified `ld`, which cannot parse a foreign architecture's
relocations when cross-compiling. Applied the same fix to both; these
are the only two `ld -r` sites left in the pristine 4.100 tree.

Build-verified locally for the gnutls and ldap variants on
x86_64/musl.

Signed-off-by: Daniel Golle <redacted>