Various trivial fixes

# gpg: Signature made Wed 21 Aug 2019 12:19:11 BST
# gpg:                using RSA key CD2F75DDC8E3A4DC2E4F5173F30C38BD3F2FBE3C
# gpg:                issuer "laurent@vivier.eu"
# gpg: Good signature from "Laurent Vivier <lvivier@redhat.com>" [full]
# gpg:                 aka "Laurent Vivier <laurent@vivier.eu>" [full]
# gpg:                 aka "Laurent Vivier (Red Hat) <lvivier@redhat.com>" [full]
# Primary key fingerprint: CD2F 75DD C8E3 A4DC 2E4F  5173 F30C 38BD 3F2F BE3C

* remotes/vivier2/tags/trivial-branch-pull-request:
  hw/display: Compile various display devices as common object
  hw/display/sm501: Remove unused include
  spapr_events: Rewrite a fall through comment
  vl: Rewrite a fall through comment
  target/ppc: Rewrite a fall through comment
  hw/ipmi: Rewrite a fall through comment
  hw/dma/omap_dma: Move switch 'fall through' comment to correct place
  json: Move switch 'fall through' comment to correct place
  hw/net/e1000: Fix erroneous comment
  .gitignore: ignore some vhost-user* related files
  configure: fix sdl detection using sdl2-config
  configure: remove obsoleted $sparc_cpu variable
  misc: fix naming scheme of compatiblity arrays
  test: Use g_strndup instead of plain strndup

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