Merge remote-tracking branch 'remotes/huth-gitlab/tags/pull-request-2020-12-18' into...

* Compile QEMU with -Wimplicit-fallthrough=2 to avoid bugs in
  switch-case statements

# gpg: Signature made Fri 18 Dec 2020 08:19:04 GMT
# 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]
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* remotes/huth-gitlab/tags/pull-request-2020-12-18:
  configure: Compile with -Wimplicit-fallthrough=2
  hw/rtc/twl92230: Add missing 'break'
  bsd-user: Silence warnings about missing fallthrough statement
  tests/fp: Do not emit implicit-fallthrough warnings in the softfloat tests
  tcg/optimize: Add fallthrough annotations
  target/sparc/win_helper: silence the compiler warnings
  target/sparc/translate: silence the compiler warnings
  accel/tcg/user-exec: silence the compiler warnings
  hw/intc/arm_gicv3_kvm: silence the compiler warnings
  target/i386: silence the compiler warnings in gen_shiftd_rm_T1
  hw/timer/renesas_tmr: silence the compiler warnings
  hw/rtc/twl92230: Silence warnings about missing fallthrough statements
  target/unicore32/translate: Add missing fallthrough annotations
  disas/libvixl: Fix fall-through annotation for GCC >= 7

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