Merge branch 'master' into ng/master

Merge branch 'master' into ng/master

* master:
  maintainer-check: do not hang
  parallel-tests: 'recheck' must depend on 'all'
  vala tests: building libraries, and more on '.vapi' files
  automake: fix botched call to 'check_user_variables'
  vala: cleanup rules are better and more complete now
  vala tests: check headers generation
  vala tests: remove redundant libtool requirements and usages
  vala tests: some enhancements
  vala tests: few adjustments and improvements
  build: use latest help2man, but without locale support