with libtool components
* SAPI targets can enable thread-safe mode and define
shared/static/program build target
* all configure scripts use the same config.cache
* phplibdir is $(top_builddir)/modules to avoid
permission problems
* sapi/*/Makefile.inc are gone
* runpath handling cleaned up
* top-level Makefile.in obsoleted through Makefile.am
* --enable-versioning uses libtool's cleaner and more
portable -export-symbols feature
