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

From Alex's pull request:
* improve cross-build KVM coverage
* new --without-default-features configure flag
* add __repr__ for ConsoleSocket for debugging
* build tcg tests with -Werror
* test 32 bit builds with fedora
* remove last traces of debian9
* hotfix for centos8 powertools repo

* Move lots of feature detection code to meson (Alex, myself)
* CFI and LTO support (Daniele)
* test-char dangling pointer (Eduardo)
* Build system and win32 fixes (Marc-André)
* Initialization fixes (myself)
* TCG include cleanup (Richard, myself)
* x86 'int N' fix (Peter)

# gpg: Signature made Wed 06 Jan 2021 09:21:25 GMT
# 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: (52 commits)
  win32: drop fd registration to the main-loop on setting non-block
  configure: move tests/qemu-iotests/common.env generation to meson
  meson.build: convert --with-default-devices to meson
  libattr: convert to meson
  cap_ng: convert to meson
  virtfs: convert to meson
  seccomp: convert to meson
  zstd: convert to meson
  lzfse: convert to meson
  snappy: convert to meson
  lzo: convert to meson
  rbd: convert to meson
  libnfs: convert to meson
  libiscsi: convert to meson
  bzip2: convert to meson
  glusterfs: convert to meson
  curl: convert to meson
  curl: remove compatibility code, require 7.29.0
  brlapi: convert to meson
  configure: remove CONFIG_FILEVERSION and CONFIG_PRODUCTVERSION
  ...

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

# Conflicts:
#	trace/meson.build

trace/meson.build

@@ -1,3 +1,4 @@
+
 specific_ss.add(files('control-target.c'))
 
 trace_events_files = []
@@ -66,7 +67,7 @@ foreach d : [
                 output: d[0],
                 input: meson.source_root() / 'trace-events',
                 command: [ tracetool, '--group=root', '--format=@0@'.format(d[1]), '@INPUT@', '@OUTPUT@' ])
-  specific_ss.add(gen)
+  specific_ss.add(when: 'CONFIG_TCG', if_true: gen)
 endforeach
 
 if 'CONFIG_TRACE_UST' in config_host