Merge remote-tracking branch 'fsf/maint'

* fsf/maint: (404 commits)
  doc: update the --verbose report format.
  doc: spell check.
  doc: stmt, not stmnt.
  doc: save width.
  doc: reformat grammar snippets.
  doc: use only @example, not @smallexample.
  doc: style changes.
  doc: minor fixes to "Understanding" section
  tests: minor fixes/simplifications
  tests: be robust to quote style.
  maint: update gnulib.
  tests: be robust to POSIXLY_CORRECT being defined.
  doc: fix environment issues.
  regen.
  tests: fix regressions.
  glr: fix ambiguity reports.
  doc: stylistic improvements.
  maint: address sc_prohibit_doubled_word.
  maint: address sc_prohibit_always-defined_macros.
  maint: address sc_bindtextdomain, sc_program_name and sc_prohibit_HAVE_MBRTOWC.
  ...