Log Message:
automake: update to 1.16.2.

New in 1.16.2:

* New features added

  - add zstd support and the automake option, dist-zstd.

* Miscellaneous changes

  - automake no longer requires a @setfilename in each .texi file

* Bugs fixed

  - When cleaning the compiled python files, '\n' is not used anymore in the
    substitution text of 'sed' transformations.  This is done to preserve
    compatibility with the 'sed' implementation provided by macOS which
    considers '\n' as the 'n' character instead of a newline.
    (automake bug#31222)

  - For make tags, lisp_LISP is followed by the necessary space when
    used with CONFIG_HEADERS.
    (automake bug#38139)

  - The automake test txinfo-vtexi4.sh no longer fails when localtime
    and UTC cross a day boundary.

  - Emacsen older than version 25, which require use of
    byte-compile-dest-file, are supported again.