Merge remote-tracking branch 'remotes/huth-gitlab/tags/pull-request-2020-09-03' into staging

* Cirrus-CI improvements and fixes (compile with -Werror & fix for 1h problem)
* Two build system fixes to fix some failures the CI
* One m68k QOMification patch
* Some trivial qtest patches
* Some small improvements for the Gitlab CI

# gpg: Signature made Thu 03 Sep 2020 12:04:32 BST
# gpg:                using RSA key 27B88847EEE0250118F3EAB92ED9D774FE702DB5
# gpg:                issuer "thuth@redhat.com"
# gpg: Good signature from "Thomas Huth <th.huth@gmx.de>" [full]
# gpg:                 aka "Thomas Huth <thuth@redhat.com>" [full]
# gpg:                 aka "Thomas Huth <huth@tuxfamily.org>" [full]
# gpg:                 aka "Thomas Huth <th.huth@posteo.de>" [unknown]
# Primary key fingerprint: 27B8 8847 EEE0 2501 18F3  EAB9 2ED9 D774 FE70 2DB5

* remotes/huth-gitlab/tags/pull-request-2020-09-03:
  gitlab-ci.yml: Set artifacts expiration time
  gitlab-ci.yml: Run check-qtest and check-unit at the end of the fuzzer job
  gitlab/travis: Rework the disabled features tests
  libqtest: Rename qmp_assert_error_class() to qmp_expect_error_and_unref()
  tests/qtest/ipmi-kcs: Fix assert side-effect
  tests/qtest/tpm: Declare input buffers const and static
  tests/qtest/ahci: Improve error handling (NEGATIVE_RETURNS)
  hw/m68k: QOMify the mcf5206 system integration module
  configure: Add system = 'linux' for meson when cross-compiling
  meson: fix keymaps without qemu-keymap
  cirrus.yml: Split FreeBSD job into two parts
  cirrus.yml: Update the macOS jobs to Catalina
  cirrus.yml: Compile macOS with -Werror
  cirrus.yml: Compile FreeBSD with -Werror
  configure: Fix atomic64 test for --enable-werror on macOS

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>