lib/generic/lru: try to resolve alignof warnings

We run meson with -std=gnu11, but apparently some compiler still
complained about it.  Unfortunately it wouldn't be easy to use
standard C11 in this case.
27 jobs for <span class="ref-name">alignof</span> in 3 minutes and 57 seconds (queued for 3 seconds)
Status Job ID Name Coverage
  Build
passed #259440
docker linux amd64
archive

00:00:59

passed #259441
docker linux amd64
build

00:01:11

passed #259442
docker linux amd64
build-asan

00:01:13

passed #259443
docker
kres-gen

00:00:30

 
  Test
passed #259444
docker delayed
build:darwin

00:00:21

passed #259445
docker linux amd64
deckard

00:02:19

passed #259446
docker delayed
doc

00:01:04

passed #259447
dind
docker

00:02:04

passed #259448
docker delayed
lint:other

00:00:45

passed #259449
docker linux amd64 delayed
lint:pedantic

00:00:40

passed #259450
docker linux amd64
lint:scan-build

00:01:35

passed #259451
docker linux amd64
lint:tidy

00:02:18

canceled #259452
privileged
pkg:epel-7

00:00:06

canceled #259453
privileged
pkg:fedora-29

00:00:06

passed #259454
docker linux amd64
respdiff:basic

00:01:49

passed #259455
docker linux amd64 delayed
test:valgrind

00:00:59

 
  Extended
canceled #259457
respdiff
fwd-tls6-kresd.udp6

canceled #259458
respdiff
fwd-udp6-kresd.udp6

canceled #259462
respdiff
fwd-udp6-unbound.tcp6

canceled #259463
respdiff
fwd-udp6-unbound.tls6

canceled #259461
respdiff
fwd-udp6-unbound.udp6

canceled #259460
respdiff
iter.tls6

canceled #259459
respdiff
iter.udp6

canceled #259456
docker linux amd64
pytests

canceled #259464
respdiff
resperf:fwd-tls6.udp-asan

canceled #259465
respdiff
resperf:fwd-udp6.udp-asan

canceled #259466
respdiff
resperf:iter.udp-asan