Start building libdecnumber at the top-level:

	* Makefile.def: Add new libdecnumber host_module.  Make all-gcc
	depend on all-libdecnumber.
	* configure.in (host_libs): Include libdecnumber.
	* Makefile.in: Regenerate.
	* configure: Likewise.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@107659 138bc75d-0d04-0410-961f-82ee72b054a4