make resolver->zspill atomic to prevent potential deadlock

(cherry picked from commit 62abb6aa)
67 jobs for !2765 with 1486-threadsanitizer-lock-order-inversion-potential-deadlock-dns_resolver_createfetch-vs-v9_14 in 42 minutes and 17 seconds (queued for 3 seconds)
detached
Status Job ID Name Coverage
  Precheck
passed #474629
amd64 linux
🐞:sid:amd64

00:01:13

passed #474627
amd64 linux
autoreconf:sid:amd64

00:00:39

passed #474628
amd64 linux
misc:sid:amd64

00:00:21

 
  Build
passed #474642
amd64 linux
asan:sid:amd64

00:02:38

passed #474646
amd64 freebsd
clang:freebsd11.3:amd64

00:01:27

passed #474647
amd64 freebsd
clang:freebsd12.0:amd64

00:01:14

passed #474648
amd64 openbsd
clang:openbsd6.5:amd64

00:36:21

passed #474643
amd64 linux
clang:stretch:amd64

00:01:47

passed #474644
i386 linux
clang:stretch:i386

00:01:47

passed #474630
amd64 linux
gcc:alpine3.10:amd64

00:02:55

passed #474641
amd64 linux
gcc:bionic:amd64

00:01:57

passed #474636
amd64 linux
gcc:buster:amd64

00:03:07

passed #474631
amd64 linux
gcc:centos6:amd64

00:02:15

passed #474632
amd64 linux
gcc:centos7:amd64

00:02:03

passed #474633
amd64 linux
gcc:centos8:amd64

00:02:16

passed #474639
amd64 linux
gcc:fedora31:amd64

00:02:54

passed #474634
amd64 linux
gcc:jessie:amd64

00:02:41

passed #474637
amd64 linux
gcc:sid:amd64

00:02:54

passed #474638
i386 linux
gcc:sid:i386

00:01:51

passed #474635
amd64 linux
gcc:stretch:amd64

00:04:42

passed #474640
amd64 linux
gcc:xenial:amd64

00:02:48

passed #474650
amd64 windows
msvc:windows:amd64

00:03:35

passed #474649
amd64 linux
nolibtool:sid:amd64

00:02:10

passed #474645
amd64 linux
pkcs11:sid:amd64

00:01:41

 
  Unit
passed #474663
amd64 linux
unit:asan:sid:amd64

00:01:03

passed #474666
amd64 freebsd
unit:clang:freebsd11.3:amd64

00:00:25

passed #474667
amd64 freebsd
unit:clang:freebsd12.0:amd64

00:00:21

passed #474664
amd64 linux
unit:clang:stretch:amd64

00:00:44

passed #474651
amd64 linux
unit:gcc:alpine3.10:amd64

00:00:46

passed #474662
amd64 linux
unit:gcc:bionic:amd64

00:00:42

passed #474657
amd64 linux
unit:gcc:buster:amd64

00:00:45

passed #474652
amd64 linux
unit:gcc:centos6:amd64

00:00:46

passed #474653
amd64 linux
unit:gcc:centos7:amd64

00:00:50

passed #474654
amd64 linux
unit:gcc:centos8:amd64

00:00:51

passed #474660
amd64 linux
unit:gcc:fedora31:amd64

00:00:45

passed #474655
amd64 linux
unit:gcc:jessie:amd64

00:00:30

passed #474658
amd64 linux
unit:gcc:sid:amd64

00:00:47

passed #474659
i386 linux
unit:gcc:sid:i386

00:00:44

passed #474656
amd64 linux
unit:gcc:stretch:amd64

00:00:58

passed #474661
amd64 linux
unit:gcc:xenial:amd64

00:00:46

passed #474668
amd64 linux
unit:nolibtool:sid:amd64

00:01:06

passed #474665
amd64 linux
unit:pkcs11:sid:amd64

00:00:43

 
  System
passed #474761
amd64 linux
system:asan:sid:amd64

00:12:04

passed #474683
amd64 freebsd
system:clang:freebsd11.3:amd64

00:06:42

passed #474684
amd64 freebsd
system:clang:freebsd12.0:amd64

00:06:38

passed #474669
amd64 linux
system:gcc:alpine3.10:amd64

00:08:21

passed #474691
linux amd64
system:gcc:bionic:amd64

00:10:17

passed #474675
amd64 linux
system:gcc:buster:amd64

00:08:15

passed #474690
linux amd64
system:gcc:centos6:amd64

00:06:30

passed #474671
amd64 linux
system:gcc:centos7:amd64

00:07:01

passed #474672
amd64 linux
system:gcc:centos8:amd64

00:07:17

passed #474678
amd64 linux
system:gcc:fedora31:amd64

00:08:21

passed #474689
linux amd64
system:gcc:jessie:amd64

00:06:34

passed #474676
amd64 linux
system:gcc:sid:amd64

00:07:09

passed #474677
i386 linux
system:gcc:sid:i386

00:07:14

passed #474674
amd64 linux
system:gcc:stretch:amd64

00:06:58

passed #474679
amd64 linux
system:gcc:xenial:amd64

00:07:09

passed #474685
amd64 linux
system:nolibtool:sid:amd64

00:06:57

passed #474682
amd64 linux
system:pkcs11:sid:amd64

00:06:52

failed #474692
linux amd64
system:asan:sid:amd64

00:13:13

failed #474681
amd64 linux
system:asan:sid:amd64

00:09:30

failed #474680
amd64 linux
system:gcc:bionic:amd64

00:09:40

failed #474670
amd64 linux
system:gcc:centos6:amd64

00:07:07

failed #474673
amd64 linux
system:gcc:jessie:amd64

00:06:53

 
  Docs
passed #474686
amd64 linux
docs:sid:amd64

00:01:05

 
  Postcheck
passed #474688
amd64 linux
cppcheck:gcc:sid:amd64

00:02:23

passed #474687
amd64 linux
scan-build:buster:amd64

00:10:44