Align CMSG buffers to a void* boundary, fixes crash on architectures with strict alignment

CHANGES entry

(cherry picked from commit 17212cf9)
14 jobs for 521-align-cmsg-buffers-v9_11 in 8 minutes and 36 seconds (queued for 4 seconds)
Status Job ID Name Coverage
  Precheck
passed precheck:debian:sid:amd64 #55201
amd64 docker linux

00:00:28

 
  Build
passed build:centos:centos6:amd64 #55202
amd64 docker linux

00:03:46

passed build:centos:centos7:amd64 #55203
amd64 docker linux

00:02:51

passed build:debian:sid:amd64 #55204
amd64 docker linux

00:03:25

passed build:debian:sid:i386 #55205
i386 docker linux

00:03:47

 
  Test
passed install:debian:sid:amd64 #55214
amd64 docker linux

00:02:19

passed systemtest:centos:centos6:amd64 #55210
amd64 docker linux

00:04:05

passed systemtest:centos:centos7:amd64 #55211
amd64 docker linux

00:04:03

passed systemtest:debian:sid:amd64 #55212
amd64 docker linux

00:04:08

passed systemtest:debian:sid:i386 #55213
i386 docker linux

00:04:16

passed unittest:centos:centos6:amd64 #55206
amd64 docker linux

00:00:56

passed unittest:centos:centos7:amd64 #55207
amd64 docker linux

00:00:57

passed unittest:debian:sid:amd64 #55208
amd64 docker linux

00:00:56

passed unittest:debian:sid:i386 #55209
i386 docker linux

00:00:47