[SV 58735] Define the order that makefiles are rebuilt.

[SV 58735] Define the order that makefiles are rebuilt.

Ensure that makefiles are rebuilt in the order in which make first
considered them, and document this behavior in the manual.

* NEWS: Add a note about the new behavior
* doc/make.text (How make Processes a Makefile): Document it.
* main.c (main): Inverse the list of makefile goals.
* read.c (read_all_makefiles): Add default makefiles to the list at
the front in reverse order, the same way other makefiles are added.
* tests/scripts/features/include: Add tests to verify rebuild order.