Merge branch 'maint'

Merge branch 'maint'

* maint:
  sync: update files from upstream with "make fetch"
  maintcheck: remove outdated whitelisting
  tar: format 'ustar' cannot support UID/GID longer than 21 bits
  docs: issues with configure substitutions in TESTS
  tests: avoid possible autotools caching issues (automake bug#13832)
  tests: rename some with more descriptive names
  docs: add myself and Ralf Wildenhues as authors
  authors: add myself
  dry-run: don't get confused by '-I' option
  tests: avoid a spurious failure with the Korn Shell
  dry-run: with GNU make, prefer $(MFLAGS) over $(MAKEFLAGS)
  header vars: can determine whether we are running under GNU make
  NEWS: improve wording for automake bug#13514 fix
  NEWS: document fix for automake bug#13514