Update automake to version 1.16.5 / rev 57 via SR 933575
    
    https://build.opensuse.org/request/show/933575
    by user dirkmueller + dimstar_suse
    - update to 1.16.5:
      - PYTHON_PREFIX and PYTHON_EXEC_PREFIX are now set according to
        Python's sys.* values only if the new configure option
        --with-python-sys-prefix is specified. Otherwise, GNU default values
        are used, as in the past. (The change in 1.16.3 was too incompatible.)
      - consistently depend on install-libLTLIBRARIES.
      - use const for yyerror declaration in bison/yacc tests.
      - Common top-level files can be provided as .md; the non-md version is
        used if both are present:
          AUTHORS ChangeLog INSTALL NEWS README README-alpha THANKS
      - CTAGS, ETAGS, SCOPE variables can be set via configure.
      - Silent make output for custom link commands.
      - New option "no-dist-built-sources" skips generating $(BUILT_SOURCES)
        before building the tarball as part of "make