Merge branch '3.2-maint'

* 3.2-maint:
  test: Make subst_env_in_string not depend on existing environment
  Update source code style according to uncrustify
  Add uncrustify config and make rule
  Source code style tweaks
  Minor tweaking to comments
  Only log "Disabling direct mode" once when failing to read include file

diff --cc HACKING.txt
Simple merge