configure.ac: Revert 2005-03-25's patch.

* configure.ac: Revert 2005-03-25's patch.  Propagate MULTIlib
settings to sub Makefiles.
(GCJH, ZIP): Prefix with top_builddir.
* configure: Rebuild.
* external/w3c_dom/Makefile.am (MULTIBUILDTOP): Don't override.
* external/w3c_dom/Makefile.in: Rebuild.
* external/sax/Makefile.am (MULTIBUILDTOP): Don't override.
* external/sax/Makefile.in: Rebuild.

From-SVN: r97139