native only
* test-build.mk: handle partial holes in a more generic manner
* Makefile.in: m4 depends on libiberty
also updated dates in test-build.mk and build-all.mk
locations, pass them down to the programs that need this info
* build-all.mk: added a 'native' target, to 3stage the native toolchain
(also updated dates in test-build.mk and build-all.mk)