* automake.in ($config_header_location): Remove. Use

* automake.in ($config_header_location): Remove.  Use
%ac_config_files_location instead.
(rewrite_inputs_into_dependencies): Do not prepend $(top_builddir)/
at the top-level.
(handle_configure): Use rewrite_inputs_into_dependencies to
distribute and compute AC_CONFIG_HEADERS dependencies.
(scan_autoconf_traces) <AC_CONFIG_HEADERS>: Fill
%ac_config_files_location.
* lib/am/remake-hdr.am ($(srcdir)/%CONFIG_HIN%): Rename as ...
(%CONFIG_HIN%): ... this.  $(srcdir) is already added in
scan_autoconf_traces.
* tests/Makefile.am (TESTS): Add confh5.test.
* tests/confh5.test: New file.