Remove the "gnits" option; it prohibits my using "+" as a version

Remove the "gnits" option; it prohibits my using "+" as a version
string suffix, and all it does (beyond the default "gnu" option)
is to _require_ the THANKS file.
* configure.ac (AM_INIT_AUTOMAKE): Remove it.

Remove all AUTOMAKE_OPTIONS settings in Makefile.am files.
* tests/chgrp/Makefile.am, tests/chmod/Makefile.am:
* tests/chown/Makefile.am, tests/cp/Makefile.am:
* tests/du/Makefile.am, tests/expr/Makefile.am:
* tests/factor/Makefile.am, tests/general/Makefile.am:
* tests/install/Makefile.am, tests/ln/Makefile.am:
* tests/ls/Makefile.am, tests/mkdir/Makefile.am:
* tests/mv/Makefile.am, tests/readlink/Makefile.am:
* tests/rm/Makefile.am, tests/rmdir/Makefile.am:
* tests/seq/Makefile.am, tests/stty/Makefile.am:
* tests/tee/Makefile.am, tests/touch/Makefile.am: