configure.ac: Add tool checks for READELF and READELF_FOR_TARGET.

2011-11-09  Roland McGrath  <mcgrathr@google.com>
* configure.ac: Add tool checks for READELF and READELF_FOR_TARGET.
* configure: Rebuild.
* Makefile.def (flags_to_pass): Add READELF_FOR_TARGET.
* Makefile.tpl (READELF, READELF_FOR_TARGET): New variables.
(HOST_EXPORTS): Add READELF, READELF_FOR_TARGET.
(BASE_FLAGS_TO_PASS): Add READELF_FOR_TARGET.
(BASE_TARGET_EXPORTS, EXTRA_HOST_FLAGS, EXTRA_TARGET_FLAGS):
Add READELF.
* Makefile.in: Rebuild.

From-SVN: r181230