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.
