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

* avoid deprecation warnings for SASL on macOS 10.11 or newer
* fix -readconfig when config blocks have an id (like [chardev "qmp"])
* Error* initialization fixes
* Improvements to ESP emulation (Mark)
* Allow creating noreserve memory backends (David)
* Improvements to query-memdev (David)
* Bump compiler to C11 (Richard)
* First round of SVM fixes from GSoC project (Lara)

# gpg: Signature made Wed 16 Jun 2021 16:37:49 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: (45 commits)
  configure: Remove probe for _Static_assert
  qemu/compiler: Remove QEMU_GENERIC
  include/qemu/lockable: Use _Generic instead of QEMU_GENERIC
  util: Use unique type for QemuRecMutex in thread-posix.h
  util: Pass file+line to qemu_rec_mutex_unlock_impl
  util: Use real functions for thread-posix QemuRecMutex
  softfloat: Use _Generic instead of QEMU_GENERIC
  configure: Use -std=gnu11
  target/i386: Added Intercept CR0 writes check
  target/i386: Added consistency checks for CR0
  target/i386: Added consistency checks for VMRUN intercept and ASID
  target/i386: Refactored intercept checks into cpu_svm_has_intercept
  configure: map x32 to cpu_family x86_64 for meson
  hmp: Print "reserve" property of memory backends with "info memdev"
  qmp: Include "reserve" property of memory backends
  hmp: Print "share" property of memory backends with "info memdev"
  qmp: Include "share" property of memory backends
  qmp: Clarify memory backend properties returned via query-memdev
  hostmem: Wire up RAM_NORESERVE via "reserve" property
  util/mmap-alloc: Support RAM_NORESERVE via MAP_NORESERVE under Linux
  ...

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