bug#81558: implementation of filename-length-max

Hi,

In a package whose Makefile.am has

  AUTOMAKE_OPTIONS = filename-length-max=99

I get this error during "make dist":

groff-1.25.0.rc2.6-9df222-modified/doc/groff.html.node/Manipulating-Type-Size-and-Vertical-Spacing.html
groff-1.25.0.rc2.6-9df222-modified/src/roff/groff/tests/do-not-abort-applying-tr-request-to-non-char.sh
groff-1.25.0.rc2.6-9df222-modified/src/roff/groff/tests/backslash-exclamation-early-does-not-fail.sh
groff-1.25.0.rc2.6-9df222-modified/src/roff/groff/tests/roman-format-register-interpolation-works.sh
groff-1.25.0.rc2.6-9df222-modified/src/roff/groff/tests/alpha-format-register-interpolation-works.sh
groff-1.25.0.rc2.6-9df222-modified/src/roff/groff/tests/stringup-request-transforms-non-basic-latin.sh
groff-1.25.0.rc2.6-9df222-modified/src/roff/groff/tests/device-control-special-character-handling.sh
groff-1.25.0.rc2.6-9df222-modified/src/roff/groff/tests/error-no-space-between-dt-or-wh-arguments.sh
groff-1.25.0.rc2.6-9df222-modified/src/roff/groff/tests/current-language-and-environment-in-sync.sh
groff-1.25.0.rc2.6-9df222-modified/src/roff/groff/tests/do-not-crash-on-mismatched-diversion-request.sh
groff-1.25.0.rc2.6-9df222-modified/src/roff/groff/tests/evc-request-produces-no-output-if-invalid.sh
groff-1.25.0.rc2.6-9df222-modified/src/roff/groff/tests/device-control-escapes-express-basic-latin.sh
groff-1.25.0.rc2.6-9df222-modified/src/roff/groff/tests/backslash-X-is-transparent-to-hyphenation.sh
groff-1.25.0.rc2.6-9df222-modified/src/roff/groff/tests/fp-request-does-not-traverse-directories.sh
groff-1.25.0.rc2.6-9df222-modified/src/roff/groff/tests/device-request-passes-most-escape-sequences.sh
groff-1.25.0.rc2.6-9df222-modified/src/roff/groff/tests/do-not-crash-on-backslash-X-if-font-invalid.sh
groff-1.25.0.rc2.6-9df222-modified/src/roff/groff/tests/substring-request-on-invalid-range-is-no-op.sh
groff-1.25.0.rc2.6-9df222-modified/src/roff/groff/tests/do-not-loop-infinitely-when-breaking-cjk.sh
groff-1.25.0.rc2.6-9df222-modified/src/roff/groff/tests/so-request-accepts-embedded-space-in-arg.sh
groff-1.25.0.rc2.6-9df222-modified/src/roff/groff/tests/backslash-right-brace-ends-string-definition.sh
groff-1.25.0.rc2.6-9df222-modified/src/roff/groff/tests/stringdown-request-rejects-request-names.sh
groff-1.25.0.rc2.6-9df222-modified/src/roff/groff/tests/double-do-request-does-not-fail-assertion.sh
groff-1.25.0.rc2.6-9df222-modified/src/roff/groff/tests/backslash-s-works-with-single-digit-argument.sh
groff-1.25.0.rc2.6-9df222-modified/src/roff/groff/tests/composite-nodes-produce-approximate-output.sh
groff-1.25.0.rc2.6-9df222-modified/src/roff/groff/tests/handle-right-brace-escape-as-macro-argument.sh
groff-1.25.0.rc2.6-9df222-modified/src/preproc/tbl/tests/do-not-segv-on-span-only-table-description.sh
groff-1.25.0.rc2.6-9df222-modified/src/preproc/tbl/tests/do-not-segv-when-backslash-R-in-text-block.sh
groff-1.25.0.rc2.6-9df222-modified/src/preproc/tbl/tests/passes-through-input-with-eighth-bit-set.sh
groff-1.25.0.rc2.6-9df222-modified/src/preproc/tbl/tests/do-not-segv-on-invalid-vertical-span-entry.sh
groff-1.25.0.rc2.6-9df222-modified/src/preproc/tbl/tests/save-and-restore-hyphenation-parameters.sh
groff-1.25.0.rc2.6-9df222-modified/src/preproc/soelim/tests/passes-through-input-with-eighth-bit-set.sh
groff-1.25.0.rc2.6-9df222-modified/src/preproc/grn/tests/passes-through-input-with-eighth-bit-set.sh
groff-1.25.0.rc2.6-9df222-modified/src/preproc/pic/tests/do-not-crash-when-reading-macro-arguments.sh
groff-1.25.0.rc2.6-9df222-modified/src/preproc/pic/tests/passes-through-input-with-eighth-bit-set.sh
groff-1.25.0.rc2.6-9df222-modified/src/preproc/eqn/tests/passes-through-input-with-eighth-bit-set.sh
groff-1.25.0.rc2.6-9df222-modified/src/preproc/eqn/tests/diagnostics-report-correct-line-numbers.sh
groff-1.25.0.rc2.6-9df222-modified/src/devices/grops/tests/device-extension-command-import-works.sh
groff-1.25.0.rc2.6-9df222-modified/tmac/tests/doc_do-not-loop-infinitely-when-shortening-headers.sh
error: the above filenames are too long
make[2]: *** [Makefile:16208: distdir-am] Error 1
make[2]: Leaving directory '/groff-git/groff/bb'
make[1]: *** [Makefile:16199: distdir] Error 2
make[1]: Leaving directory '/groff-git/groff/bb'
make: *** [Makefile:16317: dist] Error 2

Some of these mentioned files have a length of 99 characters.

Why does the error complain not only about files that are *longer* than
99 characters, but also about files that are *exactly* 99 characters long?

The generated Makefile.in has

        @if test -z "$(am__skip_length_check)" && find "$(distdir)" -type f -print | \
          grep '^...................................................................................................' 1>&2; then \
          echo 'error: the above filenames are too long' 1>&2; \
          exit 1; \
        else :; fi

This grep expression has 99 dots. It should have 100 dots, no?

Bruno