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.

(cherry picked from commit 326a334b)
51 jobs for !2209 with 1171-alpine-linux-tweaks-v9_14 in 30 minutes and 44 seconds (queued for 6 seconds)
detached
Status Job ID Name Coverage
  Precheck
passed #289460
amd64 linux
🐞:sid:amd64

00:00:38

passed #289459
amd64 linux
misc:sid:amd64

00:00:16

 
  Build
passed #289473
amd64 linux
asan:sid:amd64

00:07:02

passed #289474
amd64 linux
clang:stretch:amd64

00:02:32

passed #289475
i386 linux
clang:stretch:i386

00:04:38

passed #289461
amd64 linux
docs:sid:amd64

00:01:02

passed #289942
amd64 linux
gcc:alpine3.10:amd64

00:02:08

passed #289472
amd64 linux
gcc:bionic:amd64

00:04:17

passed #289467
i386 linux
gcc:buster:amd64

00:01:16

passed #289463
amd64 linux
gcc:centos6:amd64

00:03:22

passed #289464
amd64 linux
gcc:centos7:amd64

00:02:56

passed #289470
amd64 linux
gcc:fedora29:amd64

00:02:57

passed #289465
amd64 linux
gcc:jessie:amd64

00:01:42

passed #289468
amd64 linux
gcc:sid:amd64

00:02:30

passed #289469
i386 linux
gcc:sid:i386

00:04:26

passed #289466
amd64 linux
gcc:stretch:amd64

00:02:04

passed #289471
amd64 linux
gcc:xenial:amd64

00:01:58

passed #289476
amd64 linux
pkcs11:sid:amd64

00:04:14

passed #289462
amd64 linux
gcc:alpine3.10:amd64

00:04:11

 
  Test
passed #289499
amd64 linux
system:asan:sid:amd64

00:07:55

passed #289944
amd64 linux
system:gcc:alpine3.10:amd64

00:06:20

passed #289497
amd64 linux
system:gcc:bionic:amd64

00:07:40

passed #289487
i386 linux
system:gcc:buster:amd64

00:07:54

passed #289479
amd64 linux
system:gcc:centos6:amd64

00:07:26

passed #289481
amd64 linux
system:gcc:centos7:amd64

00:07:31

passed #289493
amd64 linux
system:gcc:fedora29:amd64

00:08:17

passed #289483
amd64 linux
system:gcc:jessie:amd64

00:07:49

passed #289489
amd64 linux
system:gcc:sid:amd64

00:08:00

passed #289491
i386 linux
system:gcc:sid:i386

00:07:41

passed #289485
amd64 linux
system:gcc:stretch:amd64

00:07:34

passed #289659
amd64 linux
system:gcc:xenial:amd64

00:06:40

passed #289502
amd64 linux
system:pkcs11:sid:amd64

00:07:06

passed #289500
amd64 linux
unit:asan:sid:amd64

00:01:17

passed #289501
amd64 linux
unit:clang:stretch:amd64

00:00:44

passed #289478
amd64 linux
unit:gcc:alpine3.10:amd64

00:00:46

passed #289498
amd64 linux
unit:gcc:bionic:amd64

00:00:45

passed #289488
i386 linux
unit:gcc:buster:amd64

00:00:50

passed #289480
amd64 linux
unit:gcc:centos6:amd64

00:00:48

passed #289482
amd64 linux
unit:gcc:centos7:amd64

00:00:51

passed #289494
amd64 linux
unit:gcc:fedora29:amd64

00:00:54

passed #289484
amd64 linux
unit:gcc:jessie:amd64

00:00:30

passed #289490
amd64 linux
unit:gcc:sid:amd64

00:00:49

passed #289492
i386 linux
unit:gcc:sid:i386

00:00:51

passed #289486
amd64 linux
unit:gcc:stretch:amd64

00:00:46

passed #289496
amd64 linux
unit:gcc:xenial:amd64

00:00:57

passed #289503
amd64 linux
unit:pkcs11:sid:amd64

00:01:09

canceled #289940
amd64 linux
system:gcc:alpine3.10:amd64

00:02:55

failed #289661
amd64 linux
system:gcc:alpine3.10:amd64

00:07:12

failed #289660
amd64 linux
system:gcc:alpine3.10:amd64

00:07:02

failed #289477
amd64 linux
system:gcc:alpine3.10:amd64

00:08:15

failed #289495
amd64 linux
system:gcc:xenial:amd64

00:07:50