diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 7c05aae1d1..d4ca60e3f5 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -10,6 +10,20 @@ stages:
   - build
   - test
 
+.centos-centos6-amd64: &centos_centos6_amd64_image
+  image: "$CI_REGISTRY_IMAGE:centos-centos6-amd64"
+  tags:
+    - linux
+    - docker
+    - amd64
+
+.centos-centos7-amd64: &centos_centos7_amd64_image
+  image: "$CI_REGISTRY_IMAGE:centos-centos7-amd64"
+  tags:
+    - linux
+    - docker
+    - amd64
+
 .debian-jessie-amd64: &debian_jessie_amd64_image
   image: "$CI_REGISTRY_IMAGE:debian-jessie-amd64"
   tags:
@@ -100,7 +114,7 @@ stages:
     - test -w "${CCACHE_DIR}" && export PATH="/usr/lib/ccache:${PATH}"
     - ./autogen.sh
   script:
-    - ./configure --enable-developer --with-libtool --disable-static --with-atf=/usr/local --with-libidn2
+    - ./configure --enable-developer --with-libtool --disable-static --with-atf=/usr --with-libidn2 "${EXTRA_CONFIGURE}"
     - make -j${PARALLEL_JOBS_BUILD:-1} -k all V=1
   artifacts:
     expire_in: '1 hour'
@@ -178,6 +192,21 @@ precheck:debian:sid:amd64:
 #  <<: *ubuntu_xenial_i386_image
 #  <<: *build_job
 
+build:centos:centos6:amd64:
+  variables:
+    CC: gcc
+    CFLAGS: "-Wall -Wextra -O2 -g"
+    EXTRA_CONFIGURE: "--disable-warn-error"
+  <<: *centos_centos6_amd64_image
+  <<: *build_job
+
+build:centos:centos7:amd64:
+  variables:
+    CC: gcc
+    CFLAGS: "-Wall -Wextra -O2 -g"
+  <<: *centos_centos7_amd64_image
+  <<: *build_job
+
 build:clang:debian:sid:amd64:
   variables:
     CC: clang-6.0
@@ -206,6 +235,18 @@ build:debian:sid:i386:
   <<: *debian_sid_i386_image
   <<: *build_job
 
+unittest:centos:centos6:amd64:
+  <<: *centos_centos6_amd64_image
+  <<: *unit_test_job
+  dependencies:
+    - build:centos:centos6:amd64
+
+unittest:centos:centos7:amd64:
+  <<: *centos_centos7_amd64_image
+  <<: *unit_test_job
+  dependencies:
+    - build:centos:centos7:amd64
+
 unittest:debian:sid:amd64:
   <<: *debian_sid_amd64_image
   <<: *unit_test_job
@@ -224,6 +265,18 @@ unittest:debian:sid:i386:
   dependencies:
     - build:debian:sid:i386
 
+systemtest:centos:centos6:amd64:
+  <<: *centos_centos6_amd64_image
+  <<: *system_test_job
+  dependencies:
+    - build:centos:centos6:amd64
+
+systemtest:centos:centos7:amd64:
+  <<: *centos_centos7_amd64_image
+  <<: *system_test_job
+  dependencies:
+    - build:centos:centos7:amd64
+
 systemtest:debian:sid:amd64:
   <<: *debian_sid_amd64_image
   <<: *system_test_job
diff --git a/autogen.sh b/autogen.sh
index 7add8eabc1..583b00d870 100755
--- a/autogen.sh
+++ b/autogen.sh
@@ -10,4 +10,4 @@
 # information regarding copyright ownership.
 
 # Run this script after modifying configure.in to generate configure
-autoreconf -i
+autoreconf -f -i
diff --git a/bin/tests/system/digdelv/tests.sh b/bin/tests/system/digdelv/tests.sh
index fa80a91019..6cd321e79f 100644
--- a/bin/tests/system/digdelv/tests.sh
+++ b/bin/tests/system/digdelv/tests.sh
@@ -443,23 +443,6 @@ if [ -x ${DIG} ] ; then
   if [ $ret != 0 ]; then echo_i "failed"; fi
   status=`expr $status + $ret`
 
-  n=`expr $n + 1`
-  if $FEATURETEST --with-idn
-  then
-    echo_i "checking dig +idnout ($n)"
-    ret=0
-    $DIG $DIGOPTS @10.53.0.3 +noidnout xn--caf-dma.example. > dig.out.1.test$n 2>&1 || ret=1
-    $DIG $DIGOPTS @10.53.0.3 +idnout xn--caf-dma.example. > dig.out.2.test$n 2>&1 || ret=1
-    grep "^xn--caf-dma.example" dig.out.1.test$n > /dev/null || ret=1
-    grep "^xn--caf-dma.example" dig.out.2.test$n > /dev/null && ret=1
-    grep 10.1.2.3 dig.out.1.test$n > /dev/null || ret=1
-    grep 10.1.2.3 dig.out.2.test$n > /dev/null || ret=1
-    if [ $ret != 0 ]; then echo_i "failed"; fi
-    status=`expr $status + $ret`
-  else
-    echo_i "skipping 'dig +idnout' as IDN support is not enabled ($n)"
-  fi
-
   n=`expr $n + 1`
   echo_i "checking that dig warns about .local queries ($n)"
   ret=0
diff --git a/bin/tests/system/ixfr/prereq.sh b/bin/tests/system/ixfr/prereq.sh
index affe54bfcf..0e299f4db8 100644
--- a/bin/tests/system/ixfr/prereq.sh
+++ b/bin/tests/system/ixfr/prereq.sh
@@ -9,6 +9,9 @@
 # See the COPYRIGHT file distributed with this work for additional
 # information regarding copyright ownership.
 
+SYSTEMTESTTOP=..
+. $SYSTEMTESTTOP/conf.sh
+
 if $PERL -e 'use Net::DNS;' 2>/dev/null
 then
     :
diff --git a/bin/tests/system/run.sh b/bin/tests/system/run.sh
index 600cacd5c8..0e7632ffbf 100755
--- a/bin/tests/system/run.sh
+++ b/bin/tests/system/run.sh
@@ -194,7 +194,7 @@ else
 	$SHELL clean.sh $runall $systest "$@"
 	if test -d ../../../.git
 	then
-	    git status -su --ignored $systest | \
+	    git status -su --ignored $systest 2>/dev/null | \
 	    sed -n -e 's|^?? \(.*\)|I:file \1 not removed|p' \
 	    -e 's|^!! \(.*/named.run\)$|I:file \1 not removed|p' \
 	    -e 's|^!! \(.*/named.memstats\)$|I:file \1 not removed|p'
diff --git a/bin/tests/system/statistics/prereq.sh b/bin/tests/system/statistics/prereq.sh
index 9bca4f871d..ec3fefe08a 100644
--- a/bin/tests/system/statistics/prereq.sh
+++ b/bin/tests/system/statistics/prereq.sh
@@ -9,6 +9,9 @@
 # See the COPYRIGHT file distributed with this work for additional
 # information regarding copyright ownership.
 
+SYSTEMTESTTOP=..
+. $SYSTEMTESTTOP/conf.sh
+
 if $PERL -e 'use Net::DNS;' 2>/dev/null
 then
     if $PERL -e 'use Net::DNS; die if ($Net::DNS::VERSION >= 0.76 && $Net::DNS::VERSION <= 0.77);' 2>/dev/null
diff --git a/bin/tests/system/statschannel/prereq.sh b/bin/tests/system/statschannel/prereq.sh
index ef052f5580..f3d4fd17a6 100644
--- a/bin/tests/system/statschannel/prereq.sh
+++ b/bin/tests/system/statschannel/prereq.sh
@@ -9,6 +9,9 @@
 # See the COPYRIGHT file distributed with this work for additional
 # information regarding copyright ownership.
 
+SYSTEMTESTTOP=..
+. $SYSTEMTESTTOP/conf.sh
+
 fail=0
 
 if $PERL -e 'use File::Fetch;' 2>/dev/null
diff --git a/bin/tests/system/upforwd/prereq.sh b/bin/tests/system/upforwd/prereq.sh
index affe54bfcf..0e299f4db8 100644
--- a/bin/tests/system/upforwd/prereq.sh
+++ b/bin/tests/system/upforwd/prereq.sh
@@ -9,6 +9,9 @@
 # See the COPYRIGHT file distributed with this work for additional
 # information regarding copyright ownership.
 
+SYSTEMTESTTOP=..
+. $SYSTEMTESTTOP/conf.sh
+
 if $PERL -e 'use Net::DNS;' 2>/dev/null
 then
     :
diff --git a/bin/tests/system/xfer/prereq.sh b/bin/tests/system/xfer/prereq.sh
index daa3d5d86c..b8982d610c 100644
--- a/bin/tests/system/xfer/prereq.sh
+++ b/bin/tests/system/xfer/prereq.sh
@@ -9,6 +9,9 @@
 # See the COPYRIGHT file distributed with this work for additional
 # information regarding copyright ownership.
 
+SYSTEMTESTTOP=..
+. $SYSTEMTESTTOP/conf.sh
+
 if $PERL -e 'use Net::DNS;' 2>/dev/null
 then
     if $PERL -e 'use Net::DNS; die if ($Net::DNS::VERSION >= 0.69 && $Net::DNS::VERSION <= 0.74);' 2>/dev/null