* automake.in: Use -w.

* automake.in: Use -w.
Normalize all use of `$lang . '-foo'' into `"$lang-foo"'.
(&parse_arguments): Support --Werror and --Wno-error as a
temporary hack until --warning/-W is properly implemented.
(&handle_single_transform_list): Prototype.
Be sure to define $directory.
Use `exists' instead of testing the value of a maybe undefined
hash value.
(&add_depend2, &handle_configure, &handle_footer, &file_contents)
(&handle_factored_dependencies): Use defined values.
(&scan_one_autoconf_file): Save $_.
* tests/lex2.test, tests/sinclude.test, tests/suffix3.test:
Run automake with --Wno-error.