slirp: update submodule to v4.2.0+

git shortlog
126c04acbabd7ad32c2b018fe10dfac2a3bc1210..55ab21c9a36852915b81f1b41ebaf3b6509dd8ba

5eraph (1):
      Use specific outbound IP address

Akihiro Suda (8):
      remove confusing comment that exists from ancient slirp
      add slirp_new(SlirpConfig *, SlirpCb *, void *)
      allow custom MTU
      add disable_host_loopback (prohibit connections to 127.0.0.1)
      add SlirpConfig version
      emu: remove dead code
      emu: disable by default
      fix a typo in a comment

Anders Waldenborg (1):
      state: fix loading of guestfwd state

Giuseppe Scrivano (1):
      socket: avoid getpeername after shutdown(SHUT_WR)

Jindrich Novy (1):
      Don't leak memory when reallocation fails.

Jordi Pujol Palomer (1):
      fork_exec: correctly parse command lines that contain spaces

Marc-André Lureau (60):
      Merge branch 'AkihiroSuda/libslirp-slirp4netns'
      Merge branch 'fix-typo' into 'master'
      meson: make it subproject friendly
      Merge branch 'meson' into 'master'
      misc: fix compilation warnings
      Merge branch 'fix-shutdown-wr' into 'master'
      sbuf: remove unused and undefined sbcopy() path
      sbuf: check more strictly sbcopy() bounds with offset
      sbuf: replace a comment with a runtime warning
      Replace remaining malloc/free user with glib
      tcp_attach() can no longer fail
      state: can't ENOMEM
      sbuf: use unsigned types
      sbuf: simplify sbreserve()
      dnssearch: use g_strv_length()
      vmstate: silence scan-build warning
      gitlab-ci: run scan-build
      Merge branch 'mem-cleanups' into 'master'
      libslirp.map: bind slirp_new to SLIRP_4.1 version
      meson: fix libtool versioning
      Release v4.1.0
      Merge branch '4.1.0' into 'master'
      CHANGELOG: start unreleased section
      Merge branch 'add-unix' into 'master'
      util: add G_SIZEOF_MEMBER() macro
      Check bootp_filename is not going to be truncated
      bootp: remove extra cast
      bootp: replace simple snprintf() with strcpy()
      tftp: clarify what is actually OACK m_len
      tcp_emu: add more fixme/warnings comments
      util: add slirp_fmt() helpers
      dhcpv6: use slirp_fmt()
      misc: use slirp_fmt0()
      tftp: use slirp_fmt0()
      tcp_ctl: use slirp_fmt()
      tcp_emu: fix unsafe snprintf() usages
      misc: improve error report
      Use g_snprintf()
      util: add gnuc format function attribute to slirp_fmt*
      Merge branch 'aw-guestfwd-state' into 'master'
      Merge branch 'slirp-fmt' into 'master'
      socket: remove extra label and variable
      socket: factor out sotranslate ipv4/ipv6 handling
      socket: remove need for extra scope_id variable
      socket: do not fallback on host loopback if get_dns_addr() failed
      socket: do not fallback on loopback addr for addresses in our mask/prefix
      Prepare for v4.2.0 release
      Merge branch 'translate-fix' into 'master'
      Merge branch 'release-v4.2.0' into 'master'
      changelog: post-release
      changelog: fix link
      .gitlab-ci: add --werror, treat CI build warnings as errors
      Revert "socket: remove need for extra scope_id variable"
      Teach slirp_version_string() to return vcs version
      Merge branch 'mingw-fix' into 'master'
      Merge branch 'vcs-version' into 'master'
      meson: bump required version to 0.49
      build-sys: fix NetBSD build regression
      Merge branch 'netbsd-fix' into 'master'
      build-sys: make libslirp-version.h depend on Makefile

PanNengyuan (1):
      libslirp: fix NULL pointer dereference in tcp_sockclosed

Philippe Mathieu-Daudé (1):
      Add a git-publish configuration file

Prasad J Pandit (4):
      slirp: ncsi: compute checksum for valid data length
      slirp: use correct size while emulating IRC commands
      slirp: use correct size while emulating commands
      slirp: tftp: restrict relative path access

Renzo Davoli (2):
      Add slirp_remove_guestfwd()
      Add slirp_add_unix()

Samuel Thibault (14):
      ip_reass: explain why we should not always update the q pointer
      Merge branch 'comment' into 'master'
      Merge branch 'no-emu' into 'master'
      Fix bogus indent, no source change
      ip_reass: Fix use after free
      Merge branch 'reass2' into 'master'
      Make host receive broadcast packets
      arp: Allow 0.0.0.0 destination address
      Merge branch 'warnings' into 'master'
      Merge branch 'arp_0' into 'master'
      Merge branch 'broadcast' into 'master'
      tcp_emu: Fix oob access
      Merge branch 'oob' into 'master'
      Merge branch 'master' into 'master'

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org>