* config/default.exp (get_link_files, get_target_emul): New procs;

	* config/default.exp (get_link_files, get_target_emul): New procs;
	run shell commands to extract information from configure.host and
	configure.tgt in the source tree.
	(top level): Use them to get information needed to run tests, if
	not otherwise provided.

Should allow running of at least some of the tests by releng.

	* ld-shared/elf-offset.ld: New file.  Builds a shared library, but
	gives non-zero addresses for memory region.
	* ld-shared/shared.exp: Run the non-PIC non-AIX test again using
	the new linker script.

PR ld/17962 -- not fixed, but customer has what should be an adequate
workaround.