travis: add another stage to really run everything under ASan+UBsan

This should help to catch issues like https://github.com/systemd/systemd/issues/11253
and https://github.com/systemd/systemd/issues/11251.

.travis.yml

@@ -91,6 +91,13 @@ jobs:
           after_script:
               - $CI_MANAGERS/debian.sh CLEANUP
 
+        - name: Ubuntu Xenial
+          language: bash
+          script:
+              - set -e
+              - sudo $CI_MANAGERS/xenial.sh
+              - set +e
+
         - stage: Coverity
           language: bash
           env:

travis-ci/managers/xenial.sh

@@ -0,0 +1,19 @@
+#!/bin/bash
+
+set -e
+set -x
+
+add-apt-repository ppa:pitti/systemd-semaphore -y
+apt-get update
+apt-get build-dep systemd -y
+apt-get install -y util-linux libmount-dev libblkid-dev liblzma-dev libqrencode-dev libmicrohttpd-dev iptables-dev liblz4-dev libcurl4-gnutls-dev unifont itstool kbd cryptsetup-bin net-tools isc-dhcp-client iputils-ping strace qemu-system-x86 linux-image-virtual mount libgpg-error-dev libxkbcommon-dev python-lxml python3-lxml python3-pip libcap-dev
+apt-get install -y gettext python3-evdev python3-pyparsing libmount-dev python3-setuptools ninja-build
+pip3 install meson
+
+cd $REPO_ROOT
+
+sed -i 's/2\.30/2.27/' meson.build
+
+meson --werror -Db_sanitize=address,undefined -Dsplit-usr=true build
+ninja -v -C build
+make -C test/TEST-01-BASIC clean setup run TEST_NO_QEMU=yes NSPAWN_ARGUMENTS=--keep-unit