* automake.in (handle_languages): Define %DEPBASE% conditionally

* automake.in (handle_languages): Define %DEPBASE% conditionally
on subdir-objects.  Define SUBDIROBJ.  Do not clean *_.c files
here ...
(lang_c_finish): ... do it here.
(handle_single_transform_list): Do not output specific rules for
subdir-objects files which are not renamed.  This should reduce
the size of Makefiles with lots of subdirectory sources.
* lib/depcomp: Simplify computation of dependency output, and use
DEPDIR.
* lib/am/depend2.am (%EXT%.o, %EXT%.obj, %EXT%.lo): Adjust call
to depcomp.  Compute depbase on-the-fly in generic fastdep rules
for subdir-objects.
* tests/ansi9.test: Do not grep for an explicit rule that
we no longer expect.  Really run $MAKE to make sure the chain
of rules works.
* tests/yacc5.test: Do not grep for an explicit rule that
we no longer expect.  Adjust to use set -e.