Merge remote-tracking branch 'remotes/bonzini-gitlab/tags/for-upstream' into staging

Merge remote-tracking branch 'remotes/bonzini-gitlab/tags/for-upstream' into staging

* move target configuration to default-configs/targets (myself)
* Memory failure event (Zhenwei)

# gpg: Signature made Mon 05 Oct 2020 08:14:29 BST
# gpg:                using RSA key F13338574B662389866C7682BFFBD25F78C7AE83
# gpg:                issuer "pbonzini@redhat.com"
# gpg: Good signature from "Paolo Bonzini <bonzini@gnu.org>" [full]
# gpg:                 aka "Paolo Bonzini <pbonzini@redhat.com>" [full]
# Primary key fingerprint: 46F5 9FBD 57D6 12E7 BFD4  E2F7 7E15 100C CD36 69B1
#      Subkey fingerprint: F133 3857 4B66 2389 866C  7682 BFFB D25F 78C7 AE83

* remotes/bonzini-gitlab/tags/for-upstream:
  dockerfiles: add diffutils to Fedora
  tests: tcg: do not use implicit rules
  target-i386: post memory failure event to QMP
  qapi/run-state.json: introduce memory failure event
  target-i386: seperate MCIP & MCE_MASK error reason
  meson: move sparse detection to Meson and rewrite check_sparse.py
  default-configs: remove redundant keys
  default-configs: use TARGET_ARCH key
  configure: move OpenBSD W^X test to meson
  default-configs: remove default-configs/devices for user-mode targets
  configure: remove target configuration
  configure: remove useless config-target.mak symbols
  configure: compute derivatives of target name in meson
  configure: remove dead variable
  configure: move accelerator logic to meson
  configure: rewrite accelerator defaults as tests
  configure: convert accelerator variables to meson options
  default-configs: move files to default-configs/devices/
  travis: remove TCI test

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