Merge remote-tracking branch 'remotes/stsquad/tags/pull-configure-fixes-160920-1' into staging

configure tweaks for deprecation

  - iotest fix for readlink -f
  - linux-user, report rather than assert on mmap failure
  - clean-up and re-factor the logic
  - add tilegx-linux-user to deprecated_targets_list
  - add [lm32|unicore32]-softmmu deprecated_targets_list
  - add a gitlab deprecated builds test

# gpg: Signature made Wed 16 Sep 2020 10:11:41 BST
# gpg:                using RSA key 6685AE99E75167BCAFC8DF35FBD0DB095A9E2A44
# gpg: Good signature from "Alex Bennée (Master Work Key) <alex.bennee@linaro.org>" [full]
# Primary key fingerprint: 6685 AE99 E751 67BC AFC8  DF35 FBD0 DB09 5A9E 2A44

* remotes/stsquad/tags/pull-configure-fixes-160920-1:
  configure: add [lm32|unicore32]-softmmu to deprecation logic
  gitlab: create a build-deprecated target
  configure: include tilegx-linux-user in the deprecation logic
  configure: clean-up the target-list-exclude logic
  configure: also skip deprecated targets with target-list-exclude
  configure: move deprecated feature processing to supported_target
  iotests: Drop readlink -f
  linux-user: test, don't assert addr != test in pgb_reserved_va

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