Various fixes:

  - add .github repo lockdown config
  - better handle missing symbols in elf-ops
  - protect fcntl64 with #ifdef
  - remove unused macros from test
  - fix handling of /proc/self/maps
  - avoid BAD_SHIFT in x80 softfloat
  - properly terminate on .hex EOF
  - fix configure probe on windows cross build
  - fix %r12 guest_base initialization

# gpg: Signature made Tue 07 Apr 2020 16:31:14 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-misc-fixes-070420-1:
  tcg/i386: Fix %r12 guest_base initialization
  configure: Add -Werror to PIE probe
  hw/core: properly terminate loading .hex on EOF record
  linux-user: clean-up padding on /proc/self/maps
  linux-user: factor out reading of /proc/self/maps
  softfloat: Fix BAD_SHIFT from normalizeFloatx80Subnormal
  gdbstub: fix compiler complaining
  target/xtensa: add FIXME for translation memory leak
  linux-user: more debug for init_guest_space
  tests/tcg: remove extraneous pasting macros
  linux-user: protect fcntl64 with an #ifdef
  elf-ops: bail out if we have no function symbols
  .github: Enable repo-lockdown bot to refuse GitHub pull requests

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