Add Alpine Linux to GitLab CI

Ensure BIND is continuously tested on Alpine Linux as it is commonly
used as a base for Docker containers and employs a less popular libc
implementation, musl libc.
54 jobs for !2204 with 1171-alpine-linux-tweaks in 22 minutes and 1 second (queued for 17 seconds)
detached
Status Job ID Name Coverage
  Precheck
passed #289358
amd64 linux
🐞:sid:amd64

00:01:30

passed #289356
amd64 linux
autoreconf:sid:amd64

00:00:33

passed #289357
amd64 linux
misc:sid:amd64

00:00:17

 
  Build
passed #289371
amd64 linux
asan:sid:amd64

00:03:26

passed #289374
amd64 linux
clang:stretch:amd64

00:02:39

passed #289375
i386 linux
clang:stretch:i386

00:02:17

passed #289359
amd64 linux
docs:sid:amd64

00:01:14

passed #289360
amd64 linux
gcc:alpine3.10:amd64

00:03:50

passed #289370
amd64 linux
gcc:bionic:amd64

00:02:30

passed #289365
i386 linux
gcc:buster:amd64

00:02:06

passed #289361
amd64 linux
gcc:centos6:amd64

00:02:51

passed #289362
amd64 linux
gcc:centos7:amd64

00:02:58

passed #289368
amd64 linux
gcc:fedora29:amd64

00:04:10

passed #289363
amd64 linux
gcc:jessie:amd64

00:01:43

passed #289366
amd64 linux
gcc:sid:amd64

00:02:15

passed #289367
i386 linux
gcc:sid:i386

00:03:04

passed #289364
amd64 linux
gcc:stretch:amd64

00:02:08

passed #289369
amd64 linux
gcc:xenial:amd64

00:03:06

passed #289373
amd64 linux
mutexatomics:sid:amd64

00:01:53

passed #289377
amd64 linux
nolibtool:sid:amd64

00:02:42

passed #289376
amd64 linux
pkcs11:sid:amd64

00:01:40

passed #289372
amd64 linux
rwlock:sid:amd64

00:02:24

 
  Test
passed #289400
amd64 linux
system:asan:sid:amd64

00:09:24

passed #289378
amd64 linux
system:gcc:alpine3.10:amd64

00:09:08

passed #289398
amd64 linux
system:gcc:bionic:amd64

00:08:24

passed #289608
i386 linux
system:gcc:buster:amd64

00:07:08

passed #289380
amd64 linux
system:gcc:centos6:amd64

00:07:42

passed #289382
amd64 linux
system:gcc:centos7:amd64

00:07:47

passed #289394
amd64 linux
system:gcc:fedora29:amd64

00:08:05

passed #289384
amd64 linux
system:gcc:jessie:amd64

00:07:33

passed #289390
amd64 linux
system:gcc:sid:amd64

00:08:28

passed #289392
i386 linux
system:gcc:sid:i386

00:08:29

passed #289386
amd64 linux
system:gcc:stretch:amd64

00:07:46

passed #289396
amd64 linux
system:gcc:xenial:amd64

00:07:38

passed #289407
amd64 linux
system:nolibtool:sid:amd64

00:08:24

passed #289405
amd64 linux
system:pkcs11:sid:amd64

00:08:05

passed #289402
amd64 linux
system:rwlock:sid:amd64

00:08:18

passed #289401
amd64 linux
unit:asan:sid:amd64

00:01:14

passed #289404
amd64 linux
unit:clang:stretch:amd64

00:00:49

passed #289379
amd64 linux
unit:gcc:alpine3.10:amd64

00:01:06

passed #289399
amd64 linux
unit:gcc:bionic:amd64

00:00:45

passed #289389
i386 linux
unit:gcc:buster:amd64

00:00:53

passed #289381
amd64 linux
unit:gcc:centos6:amd64

00:00:59

passed #289383
amd64 linux
unit:gcc:centos7:amd64

00:00:49

passed #289395
amd64 linux
unit:gcc:fedora29:amd64

00:01:00

passed #289385
amd64 linux
unit:gcc:jessie:amd64

00:00:33

passed #289391
amd64 linux
unit:gcc:sid:amd64

00:00:58

passed #289393
i386 linux
unit:gcc:sid:i386

00:01:04

passed #289387
amd64 linux
unit:gcc:stretch:amd64

00:00:59

passed #289397
amd64 linux
unit:gcc:xenial:amd64

00:01:05

passed #289408
amd64 linux
unit:nolibtool:sid:amd64

00:01:13

passed #289406
amd64 linux
unit:pkcs11:sid:amd64

00:00:46

passed #289403
amd64 linux
unit:rwlock:sid:amd64

00:00:52

failed #289388
i386 linux
system:gcc:buster:amd64

00:08:32