* automake.in (rule_define): If the user tries to override

* automake.in (rule_define): If the user tries to override
an Automake which has a -local variant, suggest using the
-local variant in the -Woverride diagnostic.
(handle_factored_dependencies): Register factored
rules with rule_define, and define them only in undefined
conditions.
* tests/Makefile.am (TESTS): Add override.test.
* tests/overrid.test: New file.
* tests/phony.test: Count the number of .PHONY targets.