Merge branch 'maint'

* maint:
  parallel-tests: silence an overly verbose recipe
  tests: fix some uses of 'Exit', where 'exit' should now be used instead
  maintcheck: test scripts should be executable, check for that

diff --cc Makefile.am
Simple merge

diff --cc lib/am/check.am
Simple merge

diff --cc syntax-checks.mk
Simple merge