Report positional options that were used but had no effect during archive creation

Report positional options that were used but had no effect during archive creation

* src/names.c (file_selection_option)
(file_selection_option_name): New functions.
(unconsumed_option_push, unconsumed_option_free)
(unconsumed_option_report): New functions.
(name_list_advance): Maintain a list
of eventually unconsumed options during archive creation.
Report unconsumed options, if any.

* tests/positional01.at: New test case.
* tests/positional02.at: New test case.
* tests/positional03.at: New test case.
* tests/Makefile.am: Add new test cases.
* tests/testsuite.at: Likewise.

* NEWS: Document the changes.
* configure.ac: Version 1.29.90
* doc/tar.texi: Document the changes.