Merge branch 'next'

Merge branch 'next'

* next: (64 commits)
  More minor fixups to vala support.
  Improve Vala support.
  testsuite: do not fail on systems without read permissions.
  testsuite: parallel make fixes.
  silent-rules reorganization, --enable-silent-rules switch.
  manual: Add note about parallelism and tests ordering.
  Fix maintainer-check failure.
  parallel-tests: more testsuite exposure.
  parallel-tests: let VERBOSE=yes output appear before summary.
  parallel-tests: `clean recheck' should not rerun all tests.
  parallel-tests: Fix driver for nonempty executable extension.
  Fix a couple of $(EXEEXT)-related testsuite failure.
  Document last change in NEWS.
  Fix renamed objects with subdir-objects and other languages.
  Do not remove texinfo outputs upon mostlyclean.
  testsuite: unset TESTS, TEST_LOGS, to avoid interference.
  testsuite: generate $(parallel_tests) just when needed.
  Remove superfluous line from recheck recheck-html.
  parallel-tests: redo check-html, recheck, recheck-html.
  parallel-tests: LOG_COMPILER for tests without known extension.
  ...