Merge branch 'jc/no-writev-does-not-work' into jch

* jc/no-writev-does-not-work:
  Revert "compat/posix: introduce writev(3p) wrapper"
  Revert "wrapper: introduce writev(3p) wrappers"
  Revert "sideband: use writev(3p) to send pktlines"
  Revert "cmake: use writev(3p) wrapper as needed"

diff --cc Makefile
Simple merge

diff --cc meson.build
Simple merge

diff --cc sideband.c
Simple merge